Diabetic foot ulcers are a significant clinical problem. Lyophilized type I collagen (LC) can stimulate wound healing by promoting platelet adhesion and aggregation and acting as a chemotactic factor for macrophages. The aim of the present study was to evaluate the efficacy of LC in the treatment of diabetic ulcers. Twenty patients (twelve males and eight females, age range 60-78 years) affected by non-insulin-dependent diabetes and ulcers (19 foot ulcers and 1 post-traumatic wrist ulcer) were, consecutively and at random, treated with LC or hyaluronic acid medicated gauze. The two groups were comparable in age, sex, size and etiopathogenesis of ulcers, metabolic state. The mean time for wound healing in the group treated with LC was 32.4 +/- 8.6 days, and in the group treated with hyaluronic acid medicated gauze was 49.0 +/- 11.0 days (p less than 0.001). The data suggest that LC significantly improves wound healing and is more active than medicated gauze in the treatment of diabetic ulcers.