The biological significance of histidine-containing dipeptides discovered within the composition of nitrogenous extracts of skeletal muscles at the beginning of this century is still open to question. The present investigation is concerned with the analysis of distribution and metabolism of these compounds with special reference to their effects on functional activity of membrane-linked enzymatic systems, stability of cellular membranes, muscle contractibility, etc. The proposed hypothesis on stabilizing properties of carnosine and related substances on biological membranes is based on the ability of the dipeptides to interact with lipid peroxidation products and active oxygen species and to prevent membrane damage. This remarkable antioxidative effect of carnosine reflects the high therapeutic value of this compound as an anti-inflammatory drug and a prominent tool in wound healing.