A Phase I-II clinical trial has been conducted with a retinyl acetate (RA) gel applied cervicovaginally in women having a histopathologic lesion diagnosed as mild or moderate dysplasia. With informed consent, volunteer subjects were observed and followed with Pap smears and colposcopy in a standardized protocol involving a self-administered 7-day treatment course for three successive menstrual cycles. Varying dosages of RA including placebo, 3, 6, 9, and 18 mg per 6 g of an inert vehicle were employed. A total of 50 subjects were monitored for local and systemic side effects. No intolerable side effects or disturbing toxicity was reported or detected at any of these doses. With the 18-mg dosage, significant discomfort was reported by all women. Despite associated side effects and a considerable patient effort involved in carrying out the self-administration of the gel, a high level of compliance was achieved in this trial. It has been established that women will voluntarily participate in an intervention clinical trial to determine whether retinyl acetate is an alternative method of therapy of presumed precancerous lesions of the cervix. The analysis of the side effects of the gel at the various dosage concentrations favors the selection of the 9-mg dosage for a multicenter Phase III clinical trial to determine efficacy.