The efficacy of a water-soluble bioflavonoid-ascorbic acid complex was evaluated in the treatment of fifty episodes of recurrent herpes labialis. Twenty episodes were treated with a complex of 600 mg. of water-soluble bioflavonoids and 600 mg. of ascorbic acid, administered in equal increments three times daily. Twenty episodes were treated with a complex of 1,000 mg. of water-soluble bioflavonoids and 1,000 mg. of ascorbic acid, administered in equal increments five times daily. Ten episodes were treated with a lactose placebo. The therapeutic regimen was maintained for 3 days after the recognition of the initial symptoms associated with recurrent herpes labialis. The water-soluble bioflavonoid-ascorbic acid complex was observed to reduce vesiculation and to prevent the disruption of the vesicular membrane. The therapeutic measure was found to be most effective when initiated during the prodomal stage of the disease process. Optimum remission of symptoms was observed in 4.2 +/- 1.7 days with the 600 mg. dosage of the water-soluble bioflavonoid-ascorbic acid complex. No adverse reactions were reported by any of the patients who participated in this investigation.