The objective of the study was to observe the anti-diabetic effect of Solani nigri Herba(SH). The following experimental results were derived from the measurement of the levels of glucose, GOT and GPT in the serum and weight from a group of experimental rats by way of the injection of streptozotocin as well as the oral administration of Solani nigri Herba water extracts. The glucose level in the serum significantly decreased in the Solani nigri Herba-dosed group(SH2,12.6 mg/100 g rat weight) on the 10th day. The GOT level of SHI(4.2 mg/100 g Solani nigri Herba) and SH2 in the serum slightly decreased, but no significance to compare with control group. The GPT level of SH1 and SH2 in the serum slightly decreased, but no significance to compare with control group. The weight of rat of SH1 and SH2 in the serum slightly increased, but no significance to compare with control group. In conclusion, Solani nigri Herba appeared to have significance inhibitory effects on the rise of blood sugar level in the experimentally induced diabetics.