In four patients, two men and two women aged 73, 68, 84 and 72 years respectively, reversible cholestatic liver injury was seen 28-35 days after the start of treatment with amoxycillin-clavulanic acid (Augmentin). This rare complication of amoxycillin-clavulanic acid treatment is characterized by a relatively long latent period before the onset of symptoms or biochemical abnormalities, which makes early recognition difficult. The mechanism responsible for this idiosyncratic cholestasis is unknown.