50 adult Wistar male rats were used and divided into 4 groups, i.e. normal control group, experimental Spleen Deficiency group induced by rhubarb, spontaneous recovery group and therapeutic group treated with Chinese recipe (Si Jun Zi decoction). All the animals of the 4 groups were killed simultaneously, and the jejunum and ileum were removed and processed for demonstration of gastrin cells and 5-HT cells according to immunohistochemical PAP technique. In addition, HE stained samples were prepared. The immunoreactivities of the two types of enteroendocrine cells were observed and semiquantitative estimation were performed under light microscopy. In addition, the immunoreactivities of 5-HT cells in normal control and experimental Spleen Deficiency group were measured by microspectrocytophotometer (MPV 2, Leitz). All the data were treated statistically. This study revealed that there were no obvious histological changes in the mucosa among the 4 groups. In the jejunum, the percentage of gastrin cells(+) in experimental Spleen Deficiency group was more than that of the normal control group, while the percentage of gastrin cells( ) was less than that of the normal control group. As compared with spontaneous recovery group, it showed contrary to the above result in the therapeutic group. No gastrin cells were found in the ileum in all the 4 groups. the percentage of 5-HT cells did not show significant changes in the jejunum and ileum among the 4 groups. But immuno-reactivity in the 5-HT cell was less than that of the normal control group in the jejunum of the Spleen Deficiency group.(ABSTRACT TRUNCATED AT 250 WORDS)