Penile condylomata were eradicated from 22 (54%) of 41 men whose lesions were painted twice (with a 72-hr interval) by the investigator with 8% podophyllotoxin in ethanol and from 83 (48%) of 173 men who self-administered either 0.5 to 1.0% topical preparations twice or thrice daily for three subsequent days. All regimens had identical efficacy; a higher frequency of mild local irritation in the self-medicating group may be outweighed by a relatively lower risk for hazardous systemic absorption. The rate of cure was higher when tumors afflicted the preputial cavity than the urinary meatus or penile skin and was lower when there were more than five warts, lesions grew in a plaque-like pattern, or duration of warts exceeded six months. Sixty-six men were sensitized with 2,4-dinitrochlorobenzene; the degree of response to subsequent challenge did not correlate to number or growth pattern of lesions or to cure rate.