On non-anesthetized dogs provided with the normal, denervated and aganglionic Thiry-Vella jejunal loops, the effect of thiamine tetrahydrofurfuryldisulfide (TTFD) upon the intestinal motility was studied. On the normal and denervated loops the intravenous administration of 1.5mg/kg of TTFD produced a slight rise of tone and a remarkable increase of the amplitude of rhythmic contractions for about 20 minutes or longer. In the animal anesthetized with 25 mg/kg of sodium pentobarbital, the drug also increased the motility of the normal and denervated loops as remarkably as in the animal non-anesthetized. The drug exerted no action upon the aganglionic loop. A small amount (1ml) of 5% TTFD solution which was carefully introduced into the intestinal lumen, stimulated the mucosa to elicit the mucosal intrinsic reflex the effect of which consisted of an excitation above and an inhibition below the stimulated spot. The probable site of action of the drug was discussed.