Glossary term

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.

EssentialClinicalSource quality: HighLast updated: 29 June 2026

Why this term matters

Important for balanced education and informed decision-making.

UK medical cannabis context

NICE expects prescribers to discuss harms as well as potential benefits.

What not to assume

Effects may depend on dose, route, other medicines and individual sensitivity.

Careful wording: Avoid wording that trivialises adverse effects as “just part of the journey”.

Related glossary terms

Related MCPH pages

Sources and review notes

This entry is educational vocabulary, not medical advice. Suitability, prescribing, product choice and monitoring belong with a qualified clinician or pharmacist.