The dietary effect of water extracts of Liriopis tuber(WELT) in the diabetic SD-rats on the level of blood sugar and serum cholesterol was investigated. The experimental plots divided into normal group(N), diabetic control(DC), 5% WELT-group(WELT-I) and 10% WELT-group (WELT-II). Each group was fed for 6 weeks, then continuously fed for 1 more week after streptozotocin injection. The loss of the body weight fed for one week after induction of the diabetes was 2.2~6.3% in the WELT-I and -II groups, but it was 18.6% in the DC-group. There was no significant difference in the feed intakes after diabetes induction between N-group and WELT-group, while it was significantly increased in DC-group. The feed efficiency ratios before diabetes induction were 1.70 in WELT-I group, 1.53~1.59 in the N, DC and WELT-II group, while the ratios after diabetes induction were 0.92 in DC-group, 1.51~1.83 in the N, WELT-I and -II group. While the amounts of water intakes for one week after diabetes induction was 625.4 mL in the DC-group, and it were 364.3~371.1 mL in the WELT-groups showing no significant difference with N-group. The excretion amounts of urine were 431.96 mL in DC-group for one week after diabetes induction, and it was 182~192.84 mL in WELT-groups. The ratios of liver weight against body weight were 2.74% in N-group, 2.93~2.96% in WELT-groups, but it was 4.01% in DC-group. The level of blood glucose in WELT-groups fed for one week after diabetes induction were 136.8~138.6 mg/dL showing no significant difference with N-group, but it was 357.8 mg/dL in DC-group. The level of serum triacylglycerol and serum total cholesterol were 93.8 and 68.7 mg/dL in N-group, 120.1 and 101.6 mg/dL in DC-group, 97.4~100.6 and 60.8~67.7 mg/dL in WELT-groups, respectively, showing no significant difference between N-group and WELT-groups. HDL-cholesterol/total cholesterol ratio were 0.63 in N-group, 0.57~0.67 in WELT -groups, which was significantly higher than that of DC-group(p<0.05). Atherogenic index were 0.58 in N-group, 0.49~0.74 in WELT-groups, but it was 1.32 in DC-group. The above results suggest that the WELT diets may have both preventive and curing effects against the diabetes.