Herbal products are among the most important sources of medicines being investigated for the control of different diseases, including diabetes. Scientists have found multiple plants that are effective in controlling diabetes. In this experiment, the methanolic extract of Trigonella foenumgraecum (fenugreek) seeds at 3 different concentrations (200, 300 and 400 mg/kg body weight) were administered orally to evaluate their effects on the serum and body weight parameters of the diabetic rats compared to the standard medicated and non-diabetic control groups. Therapy of methanolic extract of fenugreek and controls continued for 4 weeks, and the effects were observed on the parameters related to weight gain, liver and renal function, serum glucose levels, and lipid profile. The results showed that the effects of the methanolic extract of T. foenumgraecum were dose dependent. There was a significant (p<0.05) increase in weight gain in the groups treated with methanolic extract of fenugreek at 400 mg/kg. The serum parameters, including glucose levels, serum lipid profile, and serum enzymes of liver and kidney functions in the group treated with methanolic fenugreek extract at 400 mg/kg were comparable to those of non-diabetic group and the standard medicated group. These results showed that the fenugreek methanolic extract effectively controlled hepatic damage and improved serum parameters at 400 mg/kg dose rate. In conclusion, the methanolic extract of fenugreek should be analyzed for its components to determine effective antidiabetic agents. Further research should be done to determine a therapeutic dose of fenugreek seeds for application in the future.