For histochemical examination, excisions were taken from the prefascial lymph vessels of the dorsum of the foot in the case of 54 patients with recurrent erysipelas immediately before lymphangiography. The results obtained were compared with the data of a simultaneous histological study. In the course of the studies, the lymph vessel adenosine triphosphatase, leucine aminopeptidase, succinic dehydrogenase, nicotinic acid adenine dinucleotide(-phosρhate) diaphorase, glutamate dehydrogenase and Na- dl- α-glycerophosphate dehydrogenase activity were considered. In the inflammatory lymph vessel processes (thrombolymphangitis obliterans, endolymphangitis proliferans, perilymphangitis chronica, etc.), the activity of adenosine triphosphatase and mitochondrial (oxidative) enzymes was observed to be increased, while in lymphangiopathia obliterans of a degenerative nature they were found to be decreased. It is believed that in the processes accompanied by lumen narrowing, the infiltration of the vessel wall due to inflammatory tissue leads to the stiffening of the vessel wall, the discontinuing of its rhythmic movement, the development of edema in the distal part of the limb, and the further degeneration of the vessel wall.