Diabetes is characterised by abnormally high plasma glucose concentration and causes functional and morphological changes in many organs. This study investigated the effects of green tea extract, ginseng root, and green tea extract plus ginseng root on the micromorphology of and distribution of mast cells and goblet cells in the intestine of rats with streptozotocin (STZ)-induced diabetes. Thirty healthy Wistar albino rats were used, six in each of five groups as follows: Group A (without diabetes): as control, Group B: STZ-induced diabetes without treatment, Group C: STZ-induced diabetes treated with green tea extract alone (100 mg/kg/daily), Group D: STZ-induced diabetes treated with ginseng root alone (400 mg/kg/daily) and Group E: STZ-induced diabetes treated with a combination of green tea extract and ginseng root (dosage as in group C and D). Blood samples were analysed for blood glucose at the end of the six week experiment period. A significant decrease (P<0.05) in serum glucose was observed in treated diabetic groups C, D and E compared with untreated diabetic group B. Mast cell number was significantly lower (P<0.05) in the lamina propria and submucosa of the small intestines, but the number of goblet cells in the duodenum and jejunum was higher in the diabetic groups than in other groups (P<0.05). Goblet cell density in the small intestine tended to be higher in the untreated diabetic group than in the other groups. Green tea extract and ginseng root had no influence on villus height in the duodenum and crypt depth in the ileum of diabetic rats but both had an effect which is characterized by a lower villus height in the jejenum. Green tea extract and ginseng root promoted micromorphology of the small intestine and also caused changes in the distribution of mast and goblet cells of the intestine of diabetic rats.