Alcoholic extracts of yeast have been used as the active ingredient in medications under names such as "tissue or skin respiratory factor," Biodyne (Sperti Drug Co, Cincinnati, Ohio--now defunct), and live yeast cell derivative (LYCD). Beneficial clinical results from the use of LYCD have been reported for the treatment of burns, wounds, and hemorrhoids. The medicinal effects of LYCD have recently been localized to a protein fraction containing a mixture of several peptides. The effects of topical application of the peptide mixture on wounds were examined in diabetic mice, an animal model in which the healing process is disrupted and delayed. Full-thickness wounds were created on the backs of diabetic (DB) and nondiabetic (non-DB) mice. Half of the DB and non-DB mice were treated with 0.05 mL of LYCD after wounding and for 4 successive days. All other mice received vehicle. Wound areas were measured at Day 0 and at 2-day intervals. Mice were sacrificed at 3, 7, 10, 21, and 28 days postinjury. Differences in the extent and quality of healing appeared between DB mice receiving LYCD and DB mice receiving vehicle by day 10 (P < .0001). By 24 days postinjury, DB mice receiving LYCD had achieved 100% wound closure, whereas DB mice receiving vehicle had achieved only 31.4% wound closure. Histologic examination of wounds reflected improved wound healing in DB mice receiving LYCD as compared with those receiving vehicle. A topically applied yeast extract peptide mixture significantly attenuates wound closure and the degree of cellular reorganization of full-thickness excisional wounds of DB mice.