A method of assay alpha-galactosidase and acid phosphatase activities in single hair roots is described. Enzyme histochemical studies show that the distribution of acid phosphatase in the human hair root matches that of alpha-galactosidase. Histochemically, the main activity is located in the upper part of the sheath near the orifice of the duct of the sebaceous gland. This is confirmed by enzyme assays on different parts of the hair root after dissection. The variation in the values found in individual hair roots is improved by relating alpha-galactosidase to acid phosphatase activities. Storage experiments indicate a remarkable stability of both alpha-galactosidase and acid phosphatase in human hair roots.