We used a new optical imaging technique to compare human intravaginal coating distributions of Conceptrol (Advanced Care Products, Brunswick, NJ) and Advantage (Columbia Laboratories, Aventuna, FL). These gels are surrogates for future microbicidal gels, differing in molecular structures and biophysical properties.For each protocol, a 3-mL gel bolus was inserted to the posterior fornix while the woman was in the supine position. She then either (1) remained supine (10 min); or (2) sat up (1 min), stood up (1 min), sat down (1 min) and returned to supine for a net elapsed time of 10 min. The imaging device is sized/shaped like a phallus, and measurements while the device was inserted provide data that simulate peri-intromission coating.Coating by Advantage was more extensive and uniform than coating by Conceptrol, with smaller bare spots of uncoated epithelium. Change in posture tended to increase extent and uniformity of coating, details differing between gels.Results are consistent with predictions of mechanistic coating theory, using gel rheological data as inputs.