Prior studies have suggested that hyaluronic acid (HA), a naturally occurring glycosaminoglycan, may accelerate the healing of superficial burn wounds. To objectively assess whether exogenous HA could accelerate the rate of healing and limit scar formation in superficial wounds, 11 patients with burn injuries who were undergoing skin grafting were given two separate skin graft donor sites of similar size and depth (1" x 1" x 0.016"). In a randomized, double-blind fashion, one of these partial-thickness wounds had repeated application with 1.5% HA; 100% glycerin, which served as a control of similar viscosity, was applied to the other wound. On alternating days, photographs were taken and then analyzed with computerized digital planimetry to objectively quantitate the rate of reepithelialization. In contrary to our hypothesis, HA significantly delayed wound healing compared to the glycerin control (time to > 95% reepithelialization: 10.3 +/- 2 days HA vs. 9.1 +/- 1.6 days control; mean +/- SD). Furthermore, no difference in the resultant scar at 6 weeks and at 3 months after wounding was evident. These results demonstrate that HA retards healing of partial thickness wounds in adults.