A 54-year-old woman was admitted to our hospital because of acute liver injury. Since she had a history of having used a diet product, drug-induced liver injury (DILI) was initially considered. However, the patient was subsequently diagnosed as suffering from primary biliary cirrhosis (PBC) based on the findings of liver histology and serum anti-mitochondrial antibody positivity. Overlap syndrome between PBC and autoimmune hepatitis (AIH) was also suspected, however, serum levels of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase became normal three months later, after treatment with combination therapy comprising ursodeoxycholic acid plus bezafibrate. We therefore concluded that the liver disease in this patient was actually PBC, but that it resembled overlap syndrome or DILI. In cases of PBC, a rapid onset, as frequently seen in the case of DILI, viral hepatitis or AIH, is not common. We herein report a rare case of PBC which resembled DILI.