A histochemical study of the effect of Solcoseryl on the activities of nine enzymes, i.e. phosphorylase (P-ase), lactic dehydrogenase (LDH), malic dehydrogenase (MDH), succinic dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G-6-PDH), α-glycerophosphate dehydrogenase (α-GDH), β-hydroxybutyric dehydrogenase (β-HDH), glutamic dehydrogenase (GDH) and NAD diaphorase has been carried out on mucous membrane of the human stomach. For the demonstration of LDH, MDH, SDH, G-6-PDH, α-GDH, β-HDH, GDH and NAD diaphorase, the method of Pearse was used and for P-ase the method of Takeuchi was performed. Solcoseryl was added to each medium at the retio of one tenth, and for the controls the same volume of 0.9 % NaCl solution was added instead of Solcoseryl. The results were summarized as follows; 1) The activities of G-6-PDH and α-GDH were increased by the addition of Solcoseryl in normal mucous membrane, intestinal metaplasia and carcinoma of the stomach. 2) NAD diaphorase activity was also increased by Solcoseryl. 3) The activities of P-ase, LDH, MDH, SDH, β-HDH and GDH were not changed by Solcoseryl. 4) Solcoseryl might promote the regeneration of the gastric mucous membrane.