Abstract: A method of treating a collagenous biomaterial, such as porcine aortic valve leaflets or bovine pericardium, by exposing the biomaterial to an alcohol to inhibit in vivo calcification. The biomaterial, preferably glutaraldehyde-pretreated, is subjected to an aqueous solution of 60% to 80% lower aliphatic alcohol, such as ethanol for a period of at least 20 minutes, and preferably, 24 to 72 hours. The biomaterial is rinsed, and then stored in either a glutaraldehyde-free environment or an ethanolic solution of glutaraldehyde. In some embodiments, the treatment solutions include an additional anticalcification agent which may be a soluble salt of a metallic cation, such as Al.sup.+3 or Fe.sup.+3.