The purpose of this double-blind, placebo-controlled, comparative study was to evaluate the specific clinical efficacy and tolerance of human leukocyte interferon-alpha (2 x 10(6) IU/g) and podophyllotoxin 0.5% incorporated in a hydrophilic cream to cure genital warts. Preselected Asian women (n = 60) aged 18-40 years (mean 22.9), with a clinical and biopsy-confirmed diagnosis of genital warts, harboring 322 lesions (mean 5.36) were randomly assigned to three parallel groups to receive one of the two test drugs or placebo. Each patient received a precoded tube (40 g) containing either human leukocyte interferon-alpha, podophyllotoxin, or identically appearing placebo cream for 3 days' usage. In addition to written instructions, each subject was shown how to apply a minimal amount of trial medication on their lesions thrice daily for 3 consecutive days per week (maximum nine topical applications per week). Patients were examined on a weekly basis, and a cure was considered to be a biopsy-confirmed, total elimination of a lesion. Moreover, patients cured during the study period were spared further therapy, and were requested to return in 16 weeks to monitor for the occurrence of a relapse. The remaining patients' empty tubes were collected, and similarly precoded replacement tubes were given to continue the treatment; a total of 214 tubes were used. The study was scheduled for 16 weeks with 4 weeks of active treatment. Individuals were excluded from the study due to pregnancy, breast feeding, or the receiving of any type of antiviral therapy during the 4 weeks preceding enrollment.(ABSTRACT TRUNCATED AT 250 WORDS)