The subject invention is directed to the treatment of tissue fibrosis by administration of an effective amount of lectin. Fibrosis herein refers to the accumulation of extracellular matrix constituents that occurs following trauma, inflammation, tissue repair, immunological reactions, cellular hyperplasia, and neoplasia. Examples of tissue fibrosis include, but are not limited to, pulmonary fibrosis, cirrhosis of the liver, skin scars and keloids, adhesions, fibromatosis, atherosclerosis, and amyloidosis. The treatment is intended for a variety of mammals, including humans.