The effect of drug-loaded synthetic dressings on the contraction, epithelialization, and collagen synthesis of deep second-degree burns was followed for 21 days in 44 guinea pigs. Two symmetrical burns were inflicted on the back of each animal; the animals were then divided at random into the following test groups: Group 1 (n = 10), a prefabricated, precut, pliable, and noncracking dressing designated as Dimac (DM), versus Dimac plus 2% silver sulfadiazine (DM+); Group 2 (n = 10), Hydron loaded with 2% silver sulfadiazine (HAgS) one versus fine mesh gauze and 1% silver-sulfadiazine cream (GAgS); Group 3 (n = 12), Hydron (Hyd) versus fine mesh gauze (G); Group 4 (n = 4), fine mesh gauze versus Telfa (Tel); Group 5 (n = 6), Telfa versus Telfa; Group 6 (n = 2), gauze versus gauze. Epithelialization and contraction rates were measured at dressing changes on postburn days 6, 12, 18, and 21, with a computerized sonic digitizer. Collagen biosynthesis was measured from the wound scar on PBD 21 and expressed as relative collagen biosynthesis. Contraction on PBDs 18 to 21 was significantly lower (p less than 0.05) in the DM and DM+ treated burns. Epithelialization of the DM and DM+ treated groups on PBD 21 was significantly (p less than 0.05) higher than in the Hyd, HAgS, GAgS, and Tel treated burns, and did not differ from the G treated wounds. The relative collagen biosynthesis method was inapplicable to this burn wound model.