An 18-year-old man, admitted because of severe bleeding manifestations due to varicella thrombocytopenia was administered 800 mg/day adenine arabinoside (Ara-A) intravenously for 5 days. 2 days after the start of this treatment the bleeding phenomena became markedly reduced and a progressive increase in the platelet count was noted thereafter. Although a spontaneous improvement is known to occur in patients with varicella thrombocytopenia, the rapid clinical improvement after the Ara-A administration is suggestive for its beneficial effect in the presented patient.