This study investigated the effect of tea fungus/kombucha beverage(TF) protein concentrations and enzyme activities in serum of both normal and diabetic male rats. Sprague Dawley growing rats were randomly assigned to one control and five diabetic groups. In five diabetic groups, D control group was fed drinking water and the other groups were fed drinking water supplemented with 20 or 40% TF (20 or 40% TFD group, respectively) and 20 or 40% disinfected TF(20 or 40% TFSD group, respectively) for 7 weeks. Diabetes was experimentally induced in all five diabetic groups by streptozotocin injection after 3 week feeding. The diabetic groups were significantly decreased the body weight( 29.4~ 48.6g) compared with those in control group(72.4g). The total liver and kidney weights in all diabetic groups were similar to those in control group, but those relative to body weights in all diabetic groups were heavier than those in control group. The total spleen weight in all diabetic groups was significantly decreased compared with those in control group, but those relative to body weights in all diabetic groups were similar to those in control group. The blood glucose levels were heigher in all diabetic groups than those in control group. The alkaline phosphatase activity in serum was higher in all experimental groups than those in control group, but it was lower in 40% TFD, 20% and 40% TFSD groups than those in D control group. The GPT activity was significantly increased in D control, 20% and 40% TFD groups than in control group. The GOT activity was significantly increased in D control goup than in control group, but those in all TFD and TFSD groups were similar to control group. The total protein concentration in all diabetic groups was significantly decreased compared with that in control group, but the albumin concentration showed almost the same levels in all the experimental groups. The ratio of albumin/globulin, and hem atocrit value were significantly increased in all diabetic groups than in control group. These results show that tea fungus/kombucha beverage with which diabetic rats were fed has not recovered the decreased body weight, lowered serum total protein level, hypertrophy of liver and kidney, hyperglycemia to the normal state.