- 19 women and 9 men, aged 15-59 (mean, 35.1), who had had recurrent lip or genital infections with herpes virus (HSV) for from 1-38 years, were treated with beta-interferon gel (100,000 IU/g), self-administered 4 times daily to the affected areas. In half the patients the drug and a placebo were given in a double-blind, cross-over study. The trial lasted 30 months. Frequency of attacks, length of each attack and its severity, and the presence of itching were noted. If there was improvement in at least 2 parameters treatment was considered successful. This was the case in about 75% of the patients. The mean number of attacks per year before and during treatment with interferon was 6.8 and 3.0, respectively (p less than 0.003) and the mean length of attacks 8.2 and 4.7 days, respectively (p less than 0.001). Results of the double-blind, cross-over test were also significant, and were similar to those for the total group. These results clearly indicate that local interferon is effective treatment for genital and labial HSV infections.