Human leukocyte interferon (HLI) incorporated in ointment (4,000 units/g) applied topically for 4 weeks induced the process of "scavenging" granulation and epithelialization of stasis ulcers. This therapy had a better effect than that of the other combined local and general therapy also given in the study. A comparison of the effects of both therapies was made on nine pairs of stasis ulcers. A favorable effect of HLI on granulation and epithelialization was observed in a patient with deep burns, who had been given HLI topically in the form of powder and solution. This type of HLI activity calls for further clinical trials, especially as regards deep burns.