Background: Clonidine is a centrally acting antihypertensive known to cause dermatological adverse reactions. Urticaria is rarely reported. Case details: Oral clonidine was given to control supine hypertension in a patient receiving fludrocortisone for postural hypotension associated with therapy for Parkinson's disease. After one week, she developed erythematous, blanching, itchy papules and plaques, initially in the extremities and later becoming generalised, together with perioral oedema. Clonidine was ceased and the condition resolved as previous drug therapy was reintroduced. This reaction was considered to be of moderate severity, probably induced by clonidine, and not preventable. Conclusion: Clonidine can cause urticarial reactions and clinicians should be alert for this possibility when commencing therapy.