The dynamic friction coefficient between skin and a Teflon probe and its correlation with age, body weight, height, transepidermal water loss and skin capacitance was studied in vulvar and forearm skin of 44 healthy female volunteers. The friction coefficient of vulvar skin was 0.66 +/- 0.03 (mean +/- SEM) compared to that of forearm skin of 0.48 +/- 0.01. The difference was highly significant (p less than 0.001). Multiple-regression analysis showed that the vulvar skin friction coefficient was significantly correlated with capacitance as an indicator of stratum corneum hydration (p less than 0.01) but not with age, weight, height or transepidermal water loss. It is concluded that the high friction coefficient of vulvar skin may be due to the increased hydration of vulvar skin. Age-related differences seem to exist for transepidermal water loss and friction coefficient in forearm but not in vulvar skin.