The distribution and location of Substance P, Glucagons, Gastrin, Somatostatin, Thyrotro-phin, Adreno corticotrophic, Insulin, Pancreatic polypeptide, Calsequestrin, Synapsin, Vacoactive intestinal polypeptide in lymphoid tissue of sacculus rotundus was studied by using the immuno-histochemistry methods. The 11 above-mentioned substances were all positive in both mucus tissue and different locations and different positive cell quantities. Calsequestrin and insulin, their positive cells were mainly located in the mucus, only few positive cell could be occasionally found in lymphoid tissue. Synapsin, Substance P, Gastrin, Somatostatin, Vacoactive intestinal polypeptide and Glucagons were strong positive both in mucus tissue and in lymphoid tissue. TSH and Adreno corticotrophic were also strong positive both in mucus tissue and in lymphoid tissue, but in lymphoid tissue, many more positive cells exist in domes than in follicles. On the contrary, more Pancreatic polypeptide positive cells exist in follicles than in domes.