Pneumonia is a rare but serious and occasionally fatal complication of varicella. Two cases of varicella pneumonia were successfully treated with acyclovir in our department. We reviewed the pulmonary manifestations of varicella, the risk factors and the effect of acyclovir on varicella pneumonia on immunocompetent adults. Early, aggressive therapy with acyclovir seems to abort the catastrophic consequences of varicella pneumonia, while oral acyclovir chemoprophylaxis is probably beneficial in high-risk populations with chickenpox.