Hepatitis and acute liver insufficiency are rare adverse effects of clopidogrel in humans.6,7 Elevation of liver enzymes has been associated with clopidogrel in 1–3% of human patients,13 with 10 recorded cases of hepatitis after clopidogrel use in human literature.6,7,18, , , , –23 However, atenolol too has a 1–2% occurrence rate of elevated liver enzymes in humans.24 Theoretically, the elevated ALT values could therefore have been a combined effect of atenolol and clopidogrel, and not something caused by clopidogrel alone. The gene discussed is GPT; the disease is hepatitis A virus infection.