Atorvastatin has been associated with liver injury. We reported here two cases of aminotransferases elevation within 12 h of low-dose atorvastatin therapy. Liver functions were fully recovered to the baseline level 11 days after discontinuation of atorvastatin treatment. The possible relative risk factors included advanced age, chronic and systemic diseases, and co-administration of cytochrome P450 3A (CYP3A) enzyme-dependent metabolic drugs or its inhibitors such as clopidogrel and diltiazem. No significant transaminase elevation was observed after switching to pravastatin. Thus, pravastatin might be safer than atorvastain in patients with chronic or systemic diseases, or with co-administration of CYP3A enzyme-dependent drugs.