Anti-hypertensive drugs, including diuretics and beta-blocking drugs, belong to a group of therapeutics used by about a fourth of the Danish population. As with cytostatics, antibiotics, and topical remedies, they rather frequently cause adverse drug reactions (ADR) in the skin. No exact statistical information is available concerning the extent of such side effects. The information obtained by Danish National Board of Health's Committee on Adverse Drug Reactions shows that 10-60% of ADR from diuretics, beta-blocking agents, and anti-hypertensive drugs are dermatological. The skin symptoms are not unique for any specific drug. But certain symptoms occur more frequently than others. Thiazides can give vasculitis, a phototoxic/-allergic eruption, erythema multiforme, or eczema. The combination of amiloride (5 mg) and hydrochlorothiazide (50 mg) carries the highest number of recorded ADR; 59% of these are in the skin. Half of the skin ADR are phototoxic eczema. Furosemide may give eczema, purpura, a bullous eruption, or Steven-Johnson's syndrome in rare cases. Methyldopa can induce eczematous eruptions on hands and feet, a lichenoid eruption, a lupus erythematosus-like eruption, or purpura. Hydralazine may give lupus erythematosus-like eruptions, eczema, or urticaria. Non-specific beta-blocking drugs can induce a morbilliform rash and may aggravate psoriasis. Captopril may induce pruritus in up to 15% of the patients and skin eruptions in 2%. The most serious dermatological side effect, exfoliative dermatitis, is very rarely seen following the use of anti-hypertensive drugs or diuretics.