Collagen is a fibrous protein present in the extracellular framework of all vertebrates. Collagen type III is a 300 kD molecule that belongs to fibrillar collagens family found mainly in skin, blood vessels, liver, placenta, tongue and thymus. This collagen is directly or indirectly involved in several genetic diseases like Ehlers-Danlos type IV disease. Mouse monoclonal anti-collagen type III antibody reacts specifically with native and denatured collagen type III but not with collagen types I, II, IV, V, VI, and X. This product has also shown reactivity for rat and human collagen type III.