UK patient glossary
Understanding medical cannabis language can be difficult, especially when clinic terms, pharmacy labels, research language and patient-community slang all get mixed together. This glossary explains common cannabis terms in plain English for UK patients and carers, with a focus on education, safety and legal context rather than promotion.
Browse A-Z
What this glossary covers
THC, CBD, minor cannabinoids, terpenes and plant-compound terms.
Side effects, interactions, monitoring, routes, impairment and practical care language.
CBPMs, controlled-drug language, specialist prescribing, driving, travel and pharmacy terms.
Terms patients may hear online or in community settings, labelled carefully where informal.
Flower, oils, extracts, batches, labels, COAs and product-quality vocabulary.
Clinical trials, real-world evidence, registries and evidence-quality terms.
Start with these key terms
These terms carry the most practical weight for UK patients because they appear in prescribing, pharmacy, safety or legal conversations.
- Administration routeClinical
- Adverse drug reactionSafety
- Adverse effectClinical
- CannabinoidCannabinoids
- Cannabis-based product for medicinal useLegal / prescribing
- Cannabis flowerProduct
- Cannabis oilProduct
- CBDCannabinoids
- CBPMLegal / prescribing
- Clinical trialResearch
- Controlled drugLegal / pharmacy
- ContraindicationClinical
- DependenceSafety
- Dispensing labelPharmacy
- DoseClinical
- Drug drivingSafety / legal
- Drug-drug interactionClinical / safety
- GMC Specialist RegisterLegal / prescribing
- IndicationClinical
- InhalationAdministration
- Informed consentClinical / ethics
- InteractionClinical
- Licensed medicineLegal / prescribing
- Medical cannabisGeneral
- Medical defenceLegal / driving
- MHRARegulation
- NabiloneLicensed medicine
- NabiximolsLicensed medicine
- OnsetClinical
- Oral routeAdministration
A
Acidic cannabinoids
Acidic cannabinoids are the forms that occur naturally in the fresh plant before heating or prolonged ageing changes them. The best-known examples are THCA and CBDA. Patients may see them…
Useful
Administration route
Administration route means the way a medicine is taken, such as by mouth, under the tongue, or by inhalation through an approved vaporiser. Different routes affect how fast the medicine…
Essential
Adverse drug reaction
An adverse drug reaction is an unwanted or harmful reaction suspected to be caused by a medicine. It can be mild, such as dizziness, or more serious, such as severe mood or liver-related…
Essential
Adverse effect
An adverse effect is an unwanted effect associated with treatment. In patient-facing copy, it often overlaps with “side effect”, though formal pharmacovigilance writing may be more specific.
Essential
Aerosol
Aerosol refers to tiny particles or droplets suspended in air that can be inhaled. In cannabis discussions, patients may see it used when talking about vaporised medicine.
Context-only
Assay
In lab reporting, an assay is a test that measures how much of a substance is present in a sample. In cannabis, this often means the measured amount of THC, CBD or other cannabinoids in a…
Advanced
B
Balanced product
A balanced product usually means a product formulated to contain broadly comparable amounts of THC and CBD rather than being strongly THC-dominant or CBD-dominant.
Useful
Batch
A batch is a particular production run of a medicine, identified so it can be traced for quality control and safety reasons.
Useful
Behavioural side effect
This term refers to unwanted changes in mood, behaviour or thinking that may occur while taking a medicine. NHS information on medical cannabis includes mood and behavioural changes among…
Useful
Bioavailability
Bioavailability means how much of a medicine reaches the bloodstream in a usable form after it is taken. It can differ by route, formulation and food intake.
Useful
Black market
Black market means cannabis sold or supplied outside the legal medical and pharmacy system. Patients may encounter the term in community discussions or media coverage.
Caution
Broad-spectrum
Broad-spectrum usually describes an extract containing more than one cannabis-derived compound while claiming little or no THC. The exact meaning can vary by manufacturer.
Caution
C
Cannabinoid
A cannabinoid is a chemical compound that interacts directly or indirectly with the body’s cannabinoid-related signalling systems. In patient education, “cannabinoid” usually means…
Essential
Cannabinoid ratio
Cannabinoid ratio describes the relative amount of one cannabinoid compared with another, most commonly THC to CBD.
Useful
Cannabis-based product for medicinal use
In UK practice, this term refers to products that meet the legal definition used after the 2018 law change. NICE also uses it as part of its prescribing framework.
Essential
Cannabis flower
Cannabis flower means the dried flowering tops of the plant supplied as a medicinal product. Patients may see it listed alongside oils or capsules in specialist settings.
Essential
Cannabis oil
Cannabis oil is a liquid formulation containing cannabinoid ingredients, usually measured in drops or millilitres. It may be taken by mouth or under the tongue depending on the…
Essential
Capsule
A capsule is a solid oral dosage form containing a measured amount of medicine. In cannabis medicine discussions, this may relate to products such as nabilone capsules or other oral…
Useful
CBD
CBD, short for cannabidiol, is one of the best-known cannabinoids. NHS public information says CBD is a substance found in cannabis and notes that Epidyolex contains highly purified CBD…
Essential
CBDA
CBDA is the acidic precursor form of CBD found in the raw plant before heating or ageing changes it. Patients may see it in more detailed chemistry tables or lab reports.
Advanced
CBG
CBG, or cannabigerol, is a minor cannabinoid that patients may see mentioned in lab reports or extract descriptions.
Advanced
CBN
CBN, or cannabinol, is another minor cannabinoid often discussed in consumer and specialist cannabis spaces. It may appear on detailed potency reports or product specifications.
Advanced
CBPM
CBPM is a common abbreviation for cannabis-based medicinal product or, more formally in UK guidance, cannabis-based product for medicinal use. It is standard jargon in clinics…
Essential
Certificate of analysis
A certificate of analysis is a laboratory document that reports test results for a given sample or batch. In cannabis, it may include cannabinoid content and other quality or contaminant…
Useful
Chemovar
Chemovar means a chemically characterised variety, classified by its cannabinoid and terpene profile rather than by marketing labels such as “indica” or “sativa”.
Useful
Clinical trial
A clinical trial is a structured research study designed to test a treatment in people. Some trials compare a medicine with placebo or standard care.
Essential
Clobazam
Clobazam is an antiseizure medicine that matters in cannabis guidance because certain NICE recommendations for cannabidiol in epilepsy are specifically for cannabidiol with clobazam.
Useful
Controlled drug
A controlled drug is a medicine or substance regulated under drug-control law because of misuse and safety concerns. Some cannabis-based medicines fall into this area.
Essential
Contraindication
A contraindication is a reason a medicine should not be used, or should only be used with great caution, because the risk is too high.
Essential
Cultivar
Cultivar means a cultivated plant variety. In cannabis discussions it is generally more accurate than consumer-facing “strain”.
Useful
D
Decarboxylation
Decarboxylation is the chemical change in which acidic cannabinoids such as THCA or CBDA lose a carboxyl group, usually through heat or time, to become THC or CBD.
Useful
Dependence
Dependence means the body or mind becomes used to a medicine in a way that can make stopping difficult or lead to withdrawal symptoms. It is not identical to addiction, but the distinction…
Essential
Dispensing label
The dispensing label is the label the pharmacist places on the medicine pack when the prescription is supplied. It identifies the patient, medicine and instructions.
Essential
Distillate
Distillate is a refined cannabis extract that has been processed to concentrate certain compounds, commonly cannabinoids.
Advanced
Dose
Dose means the amount of medicine taken at one time or on one occasion. It may be expressed in sprays, drops, milligrams or another unit.
Essential
Dosage
Dosage usually refers to the planned dose and schedule over time, not just one amount taken once.
Useful
Dried flower
Dried flower is another way of describing medicinal cannabis flower supplied in a dried form.
Useful
Drug driving
Drug driving refers to offences connected with driving while impaired by drugs or with specified controlled drugs above legal limits in the body.
Essential
Drug-drug interaction
A drug-drug interaction happens when one medicine changes the effect, level or safety profile of another.
Essential
Duration of effect
Duration of effect means how long the noticeable effects of a dose last. It is not the same as onset.
Useful
Dronabinol
Dronabinol is a synthetic compound identical in structure to naturally occurring THC and is named by NICE as an example when discussing cannabis-based medicinal products.
Advanced
E
Edible
Edible usually means a cannabis-containing product eaten rather than inhaled. It is common community language, not a standard NHS prescribing term.
Caution
Effectiveness
Effectiveness refers to how well a treatment works in everyday clinical practice, outside the tighter conditions of a trial.
Useful
Efficacy
Efficacy means how well a treatment performs under controlled conditions, especially in clinical trials.
Useful
Endocannabinoid system
The endocannabinoid system is a shorthand term for the body’s own cannabinoid-related signalling network, including receptors and natural signalling molecules.
Useful
Entourage effect
The “entourage effect” is a hypothesis that multiple cannabis compounds may interact in ways that influence overall effects. It is widely used in marketing, but the evidence base is mixed…
Caution
Evidence gap
An evidence gap means there is not enough good-quality research to answer an important clinical question confidently.
Useful
Excipient
An excipient is a non-active ingredient used to help make a medicine stable, deliverable or measurable.
Advanced
Extract
Extract is a broad term for a preparation made by taking certain compounds out of plant material. Some cannabis medicines are extracts rather than whole flower.
Useful
F
Field impairment assessment
A field impairment assessment is the set of roadside tests police may use if they think someone is impaired by drugs.
Useful
First-pass metabolism
First-pass metabolism is the breakdown that happens when a medicine taken by mouth passes through the gut and liver before reaching the bloodstream.
Advanced
Flavonoids
Flavonoids are plant compounds that can contribute to colour and may contribute to broader chemical profiles. They are often mentioned alongside cannabinoids and terpenes in scientific or…
Advanced
Flower
“Flower” is the common shorthand for cannabis flower. On patient sites it should be expanded and medically contextualised rather than left as slang.
Useful
Formulation
Formulation means the way a medicine is prepared and presented, such as an oil, capsule or mouth spray.
Useful
Full-spectrum
Full-spectrum usually describes a cannabis extract that contains multiple plant compounds rather than a single isolated cannabinoid.
Caution
G
Gamma irradiation
Gamma irradiation is one method used to reduce microbial contamination in cannabis products. Patients may see it mentioned when comparing “irradiated” and “non-irradiated” batches.
Context-only
General practitioner
A GP is the patient’s general practitioner. NHS public guidance says people should not ask a GP for a referral for medical cannabis if they do not fit the limited current criteria set out…
Useful
GMC Specialist Register
The GMC Specialist Register is the register of doctors recognised as specialists. NICE says the initial prescription of most CBPMs must be made by a specialist medical practitioner on that…
Essential
Good manufacturing practice
Good manufacturing practice refers to the standards used to make medicines consistently and safely.
Useful
H
Half-life
Half-life is the time it takes for the amount of a substance in the body to reduce by about half.
Advanced
Hemp
Hemp usually refers to cannabis varieties grown under a different legal and commercial framework from prescribed medical cannabis products.
Useful
High-THC product
This phrase describes a product with a relatively high THC content compared with CBD or with another comparator product.
Useful
Hybrid
Hybrid is a common consumer label suggesting a product combines so-called sativa and indica lineage.
Caution
Humulene
Humulene is one of the terpenes that may appear in detailed cannabinoid and terpene profiles.
Advanced
I
Indica
“Indica” is a widely used consumer label for cannabis, often contrasted with “sativa”. In patient education, it is best explained as informal and imprecise rather than clinically reliable.
Caution
Indication
An indication is the condition, symptom or circumstance for which a medicine may be considered or prescribed.
Essential
Inhalation
Inhalation means medicine enters the body by being breathed in. In cannabis discussions this usually relates to vaporised, not smoked, prescribed product use.
Essential
Informed consent
Informed consent means the patient has been given enough understandable information about benefits, harms, alternatives and uncertainties to make a voluntary decision.
Essential
Interaction
Interaction is the plain-language term for one medicine, substance or health factor changing the effect or safety of another.
Essential
Intoxication
Intoxication means being affected by a substance in a way that changes thinking, coordination, judgment or behaviour.
Useful
Irradiated
“Irradiated” in this context usually means the batch has been treated with a radiation-based decontamination process to reduce microbial contamination.
Useful
Isolate
An isolate is a preparation intended to contain one main purified compound, such as CBD isolate, rather than a broader mix of plant compounds.
Useful
J
Joint
A joint is a hand-rolled cannabis cigarette. It is included only because patients may meet the word in community or media conversations.
Caution
K
L
Legacy market
“Legacy market” is a softer term sometimes used to describe illegal or previously illegal cannabis supply networks.
Caution
Licensed medicine
A licensed medicine is a medicine that has marketing authorisation for a specific use, supported by regulatory review of quality, safety and efficacy.
Essential
Limonene
Limonene is a terpene that may appear in cannabis terpene profiles and product chemistry write-ups.
Advanced
Linalool
Linalool is a terpene found in many plants and sometimes listed in cannabis chemistry profiles.
Advanced
Liver monitoring
Liver monitoring refers to blood-test follow-up used to watch for signs that a medicine may be affecting liver function.
Useful
Low-and-slow dosing
“Low-and-slow dosing” means beginning cautiously and increasing gradually if a clinician advises it. It is a common practical phrase, not a formal dosing standard on its own.
Caution
M
Medical cannabis
“Medical cannabis” is a broad public term for cannabis-based medicines used to relieve symptoms. NHS uses it as a broad term, while also stressing that prescribed products are only likely…
Essential
Medical defence
In drug-driving discussions, “medical defence” refers to the legal defence available where a specified drug was lawfully prescribed or supplied and taken in accordance with instructions.
Essential
Metabolite
A metabolite is a substance produced when the body breaks down a medicine or chemical.
Advanced
MHRA
MHRA is the UK regulator responsible for medicines and medical devices, including adverse-reaction reporting through the Yellow Card Scheme.
Essential
Minor cannabinoids
Minor cannabinoids are cannabinoids present in smaller amounts than THC or CBD, such as CBG and CBN.
Useful
Misuse
Misuse means using a medicine in a way other than intended, prescribed or safe.
Useful
Mouth spray
A mouth spray is a formulation sprayed into the mouth; Sativex is the key UK example in this space.
Useful
Myrcene
Myrcene is a terpene often highlighted in cannabis terpene lists and chemistry profiles.
Advanced
N
Nabilone
Nabilone is a medicine taken as a capsule that NHS says can be prescribed by a specialist for adults with chemotherapy-related nausea and vomiting when other treatments have not helped or…
Essential
Nabiximols
Nabiximols is the generic name for the THC:CBD mouth spray marketed as Sativex.
Essential
Non-irradiated
Non-irradiated means a batch has not undergone irradiation-based decontamination.
Context-only
Novel food
A novel food is a food that requires a safety assessment and authorisation before being sold in that category. In UK CBD discussions, this matters for OTC CBD products sold as food…
Useful
Onset
Onset means how quickly a medicine begins to produce noticeable effects after it is taken.
Essential
O
Observational study
An observational study looks at what happens in real people without randomly assigning them to treatment groups.
Useful
Off-label
Off-label means a licensed medicine is being used in a way not covered by its official licence, such as for a different condition, dose or route.
Useful
Oil drops
Oil drops are the measured drops of an oral or sublingual oil a patient is instructed to take.
Useful
Oral fluid test
An oral fluid test is a roadside saliva-based screening method used to test for certain drugs, including cannabis.
Useful
Oral route
The oral route means taking a medicine by mouth so it is swallowed.
Essential
Outcome measure
An outcome measure is the thing researchers or clinicians track to judge whether treatment is helping, such as seizure frequency, spasticity score or pain score.
Useful
Over-the-counter CBD
This means CBD products sold without prescription, often as food supplements.
Useful
P
Patient information leaflet
A patient information leaflet is the medicine leaflet supplied with a product, explaining how to take it, key warnings and possible side effects.
Essential
Patient-reported outcome
A patient-reported outcome is information about symptoms or quality of life reported directly by the patient rather than measured only by a clinician or test.
Useful
Peak effect
Peak effect is the point at which a dose is having its strongest noticeable effect.
Useful
Pharmacodynamics
Pharmacodynamics describes what a medicine does in the body, including receptor effects and clinical actions.
Advanced
Pharmacokinetics
Pharmacokinetics describes how a medicine is absorbed, distributed, metabolised and eliminated.
Advanced
Pharmacovigilance
Pharmacovigilance means ongoing safety monitoring of medicines after they are in use, including side-effect reporting.
Useful
Pharmacy dispensing
Pharmacy dispensing is the process by which a prescription medicine is prepared, labelled and supplied to the patient by a pharmacy.
Useful
Pinene
Pinene is a terpene that may appear in cannabis chemistry profiles.
Advanced
Placebo
A placebo is a comparison treatment designed not to contain the active medicine being studied, helping researchers test whether a treatment effect is real and not due only to expectation…
Useful
Plant-derived cannabinoid
This means a cannabinoid obtained from the cannabis plant rather than made as a fully synthetic compound.
Useful
Pregnancy
Pregnancy means a period when medicine risk-benefit decisions require extra caution because fetal exposure matters.
Essential
Prescription-only medicine
A prescription-only medicine is a medicine that legally requires prescription and professional oversight rather than ordinary retail sale.
Essential
Psychosis risk
Psychosis risk refers to the risk that a substance may contribute to symptoms such as hallucinations, delusional thinking or severe loss of contact with reality in some people.
Essential
Q
Qualitative test
A qualitative test tells you whether something is present rather than exactly how much there is.
Advanced
Quality assurance
Quality assurance refers to the systems and checks used to maintain product and process quality consistently.
Useful
Quantitative test
A quantitative test measures how much of a substance is present, such as a cannabinoid percentage or concentration.
Useful
R
Randomised controlled trial
An RCT is a study in which participants are randomly assigned to treatment groups so results are less likely to be distorted by bias or confounding.
Essential
Real-world evidence
Real-world evidence means evidence generated from routine clinical practice rather than only from tightly controlled trials.
Useful
Receptor
A receptor is a structure in the body that a chemical can bind to and influence. Cannabis discussions often mention cannabinoid receptors.
Useful
Registry
A registry is a structured system for collecting clinical information about patients, treatments and outcomes over time.
Useful
Repeat prescription
A repeat prescription is an ongoing supply arrangement for a medicine that continues after the initial prescription under the relevant clinical process.
Useful
Respiratory irritation
Respiratory irritation means irritation of the throat or airways that can happen with inhaled products or devices.
Useful
Retrospective study
A retrospective study looks back at existing records rather than following people forward from the start.
Advanced
Roadside drug test
A roadside drug test is the initial police screening process used when drug driving is suspected.
Useful
S
Saliva test
A saliva test is the plain-language version of “oral fluid test” used in roadside drug screening.
Useful
Sativa
“Sativa” is a common consumer label often contrasted with “indica”. In medical education it should be explained as informal, commercially influential and not reliable as a predictor of…
Caution
Schedule 2
Schedule 2 is a controlled-drug scheduling category that matters because medicinal cannabis prescribing in the UK sits within controlled-drug law.
Essential
Sedation
Sedation means a medicine causes drowsiness or reduced alertness.
Essential
Shared care
Shared care means aspects of prescribing or monitoring are shared between the initiating specialist and another prescriber under an agreed arrangement.
Essential
Side effect
A side effect is an unwanted effect that can happen while taking a medicine. NHS lists examples for medical cannabis including dizziness, tiredness, diarrhoea, nausea, hallucinations and…
Essential
Specialist prescriber
A specialist prescriber is the specialist medical practitioner who makes the initial prescribing decision for most CBPMs within the UK framework.
Essential
Spasticity
Spasticity refers to abnormal muscle stiffness and spasms.
Useful
Start low, go slow
“Start low, go slow” is a common cautious-dosing phrase meaning that increases, if any, should happen gradually and under proper advice.
Useful
Statutory medical defence
The statutory medical defence is the legal defence described in UK drug-driving guidance for patients who have taken certain specified drugs lawfully and according to instructions.
Essential
Strain
“Strain” is the common consumer term for a named cannabis variety. It is familiar, but it is not the most precise scientific or medical term.
Caution
Sublingual
Sublingual means placed under the tongue so some of the medicine may be absorbed through tissues there.
Useful
Substance misuse history
This means a person’s past or present history of problematic use of substances, including illicit cannabis or other drugs.
Essential
Synthetic cannabinoid
“Synthetic cannabinoid” can mean more than one thing. In formal medical guidance, it can include lab-made compounds identical in structure to naturally occurring cannabinoids, such as…
Caution
Synthetically derived cannabinoid
This term means a cannabinoid made through manufacturing rather than obtained directly from plant material.
Useful
Symptom diary
A symptom diary is a structured record of symptoms, timing, side effects and changes over time.
Useful
T
Terpene
Terpenes are aromatic plant compounds that contribute to smell and are often listed in cannabis chemistry profiles. Patients frequently encounter them in education and marketing content.
Essential
Terpenoid
Terpenoid is a broader chemistry term related to terpenes and their modified forms.
Advanced
THC
THC is the cannabinoid best known for causing intoxication or a “high”. NHS public guidance says it is the chemical in cannabis that makes people high, and also notes that the more THC a…
Essential
THC-dominant
THC-dominant means a product contains substantially more THC than CBD or other reference cannabinoids.
Useful
THC:CBD spray
THC:CBD spray is NICE’s descriptive wording for the nabiximols mouth spray used in certain adults with MS-related spasticity.
Essential
THCA
THCA is the acidic precursor form of THC found in the plant before heat or time converts some of it to THC.
Useful
Therapeutic window
Therapeutic window means the range within which a medicine may be helpful without causing unacceptable side effects.
Advanced
Titration
Titration means changing the dose gradually to find a balance between possible benefit and tolerability.
Essential
Tolerance
Tolerance means a person may become less responsive to the same dose over time.
Useful
Travel letter
A travel letter is the supporting letter patients may carry when travelling with a controlled medicine, showing that it was prescribed for them.
Essential
Treatment-resistant
Treatment-resistant means a condition has not responded adequately to usual treatments.
Useful
U
Unlicensed medicine
An unlicensed medicine is a medicine without a UK marketing authorisation for the product in question. GMC says many cannabis-based medicines in the UK are unlicensed, and that prescribing…
Essential
Up-titration
Up-titration means slowly increasing the dose over time, usually to improve effect while watching tolerability.
Useful
Urine drug test
A urine drug test is one type of drug test that looks for drug use markers or metabolites.
Useful
V
Vape cartridge
A vape cartridge is a pre-filled cartridge used with certain vaping devices. Patients may encounter the term online, but it is not standard NHS prescribing language for UK medical cannabis.
Caution
Vaporisation
Vaporisation means heating a product so active compounds are inhaled as vapour or aerosol rather than through combustion.
Essential
Vaporiser
A vaporiser is the device used for vaporisation.
Useful
Volatile compounds
Volatile compounds are chemicals that evaporate easily and contribute to smell; many terpenes fall into this broad category.
Advanced
W
Whole-plant extract
A whole-plant extract is an extract intended to contain a broader set of plant compounds rather than a single isolated cannabinoid.
Useful
Withdrawal
Withdrawal refers to symptoms that can happen when a medicine or substance is reduced or stopped after the body has adapted to it.
Useful
Workplace drug testing
Workplace drug testing refers to employment-related testing for drugs, which may be relevant in safety-sensitive or regulated roles.
Useful
X
X-ray irradiation
X-ray irradiation is another possible radiation-based decontamination method referenced in broader irradiation discussions.
Context-only
Y
Yellow Card Scheme
The Yellow Card Scheme is the UK system for reporting suspected side effects or adverse reactions. NHS says patients can also report side effects through Yellow Card, not only through…
Essential
Z
Zero-tolerance limit
In everyday discussion, “zero-tolerance limit” describes the very low specified legal limits applied to commonly abused drugs in drug-driving law, including cannabis (THC).
Useful
How entries are reviewed
Legal, prescribing and safety language is checked against official UK sources such as NHS, NICE, GMC, GOV.UK and MHRA guidance. Plant, product and community terms are included because patients may encounter them, but they are labelled cautiously where the language is informal, commercially shaped or scientifically imprecise.