Acute hepatitis led to abnormal coagulopathy, bleeding, and death in a nonhemophiliac infant infected with the human immunodeficiency virus, possibly due to zidovudine or ritonavir or both. Acute hepatitis during ritonavir treatment and episodes of spontaneous bleeding have been reported in patients with hemophilia. Zidovudine is associated with elevated liver enzymes, elevated bilirubin, and hepatomegaly leading to abnormal coagulopathy, bleeding, and death in adults. A temporal relationship between the start of combination antiretroviral therapy and onset of hepatosplenomegaly and rise in liver enzymes suggests that zidovudine or ritonavir, or both, are the likely cause of this adverse event. Ritonavir is believed to cause direct hepatotoxicity, probably by inducing acute mitochondrial toxicity, and may hasten reverse transcriptase inhibitor-induced liver toxicity. Liver function of patients receiving a combination of nucleoside reverse transcriptase inhibitor and protease inhibitors should be closely monitored.