The relationships among anserine (beta-alanyl-1-methyl-L-histidine), carnosine (beta-alanyl-L-histidine), free histidine, and histamine metabolism were examined in rats wounded by dorsal skin incision. Following wounding, rats were treated with either a histamine liberator (compound 48/80) or a histidine decarboxylase inhibitor (4-imidazolyl-3-amino-2-butanone). The liberator greatly enhanced wounded skin-breaking strength and collagen deposition at the wound site, while the histidine decarboxylase inhibitor reduced skin-breaking strength and collagen deposition. In the second experiment of this study, histamine or histidine treatment was shown to prevent trauma-induced reductions of tissue carnosine but was less effective in ameliorating tissue anserine loss. The results illustrate an interaction between imidazole dipeptides and stress and suggest that carnosine acts as a histidine reserve in relation to histamine synthesis during trauma.