The catchword "baboon syndrome" is used to denote a characteristic distribution pattern of systemic allergic contact dermatitis. Diffuse erythema of the buttocks, upper inner surface of the thighs, and axillae are characteristic features. We describe 3 cases provoked by ampicillin, nickel and mercury. The condition may be overlooked and suspected of being a textile dermatitis or seborrhoeic dermatitis of the elderly.