The effect of pantothenic acid supplementation and deficiency on wound healing was investigated over a one month postoperative period in rabbits. The supplemented group was injected with pentothenate (20 mg/kg of body weight/24 h) for three weeks and compared to a placebo group (0.5 ml of distilled water). Deficient animals were fed with a pantothenate free diet also for three weeks. These three experimental groups were matched against a control group. The degree of wound healing was determined by the mean of postoperative breaking strength and wound fibroblast population changes. Pantothenic acid urinary excretion measured by gas chromatography served as control of pantothenate consumption. With regard to these three parameters no significant difference has been found between placebo and controls. The average urinary elimination in the pantothenic acid group was significantly higher as far as the pantothenate supplemented group was concerned, while the deficient group showed no significant decrease when compared to controls. Chronic pre- and postoperative pantothenic acid supplementation significantly increased aponeurosis strength after surgery; it improved slightly, but not significantly the strength of the skin. Furthermore, the fibroblast content of the scar became significantly greater during the fibroblast proliferation phase after pantothenic supplementation. These data suggest that pantothenic acid induces an accelerating effect of the normal healing process. The mechanism responsible for this improvement seems to be an increase in cellular multiplication during the first postoperative period. But the exact intimate mechanism of the beneficial effect of pantothenate remains unclear.