Forty-two Tanzanian patients with genital warts were treated with 0.5% podophyllotoxin solution (Wartec) for 3 days. Thirteen patients (30.9%) were cured and a further 7 patients (16.7%) had more than 50% of lesions cleared at 6 weeks, while 19 patients were resistant to treatment. Three patients had a recurrence of lesions after an initial response. Thirty-three patients were tested for serological evidence of infection with human immunodeficiency virus (HIV) and 15 (45.5%) patients were shown to be HIV-1 antibody positive. The response to treatment was analysed in relation to HIV antibody status. The cure rate was significantly higher in HIV seronegative patients (8/18 = 44.4%) compared to HIV seropositive patients (1/15 = 6.7%) (P = 0.018). We conclude that podophyllotoxin treatment provides a useful non-hospital based treatment for genital warts, but HIV infection appears to contribute to the failure of treatment for genital warts.