Seventy-three patients with anogenital warts were randomly allocated to a double-blind comparison of treatment with trichloracetic acid (50%) and podophyllin (25%) versus podophyllin (25%) alone. There was no significant difference in the resolution of warts in the two treatment groups among patients followed for three months. Of patients free of warts at six weeks, treatment with trichloracetic acid/podophyllin required significantly fewer applications (mean 2.9) compared with podophyllin alone (mean 4.0). Five (17%) patients in the former group reported side effects but none in the latter group.