In a retrospective study, we review here the clinical presentation of patients with the biphasic form of hepatitis A, a variant of viral hepatitis characterised by an increase in ALAT levels after an initial recovery in clinical condition and laboratory tests. Twenty-one patients were diagnosed as having a biphasic form; they represent about 10% of a selected population of hepatitis A cases. Six patients were asymptomatic. Eleven patients were jaundiced, nine of them showing a "cholestatic" pattern. The second phase of the disease had a more protracted course and displayed higher ALAT levels than the first phase. The total duration of the disease was 120 +/- 28 (mean +/- SD) days, and its course was benign.