There are few reports in the literature related to sulfonylurea-induced hepatotoxicity. We describe the case of acute hepatitis induced by gliclazide, a second generation sulfonylurea. A 60-year-old woman with diabetes mellitus (type 2) developed an acute icteric hepatitis-like illness 6 weeks after the initiation of gliclazide therapy. Other causes of acute hepatocellular necrosis were excluded. Liver histology showed marked portal inflammation with lymphocytes, monocytes and eosinophils, associated with lobular inflammation (indicative of a histological pattern consistent with drug-induced hepatitis). The drug was immediately withdrawn and the patient was given glibenclamide. The patient recovered clinically and, in less than 4 weeks, her serum bilirubin and aminotransferases returned to normal levels. We believe that this is the first description of acute hepatitis caused by an idiosyncratic adverse reaction to gliclazide or to one of its metabolites. In conclusion, this case strongly suggests that gliclazide can induce acute icteric liver necro-inflammation which may be misdiagnosed clinically as acute viral hepatitis. In patients who show abnormal liver function tests, the immediate discontinuation of gliclazide is recommended.