The tubers of Bongardia chrysogonum, which are used in the folk medicine in the form of 2–3% decoction in the province of Gaziantep, are supposed to treat urinary track, prosthate disorders, and hemorrhoid. The objective of this study was to assess the effect of these tubers on some serum parameters and spleen, liver, and kidney tissues in rats. One, two, and three percent decoctions of the B. chrysogonum were prepared, and instilled into the stomach of the rats, 0.2 ml/day, for 60 days via an orogastric tube. The serum glucose, creatinine, urea, uric acid, total cholesterol, triglycerides, total protein, albumin, globulin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), lactate dehydrogenase (LDH), sodium (Na), potassium (K), calcium (Ca), chloride (Cl), phosphorus (P), and magnesium (Mg) levels were measured in the blood obtained via intracardiac catheterization on 15th, 30th, 45th, and 60th days, respectively. Overall health status of rats was assessed by histopathologic examinations and by the nitric oxide level of spleen, liver, and kidney tissues. It was found that there was a decrease in the serum levels of glucose, urea, total cholesterol, triglycerides, total protein, AST, ALT, ALP, Na, K, Cl, P, and Mg (p<0.05) while the levels of creatinine, uric acid, CK, and LDH remained unchanged (p>0.05). The serum albumin, globulin, and Ca levels risen to the normal levels in the long term (>30days) following a significant decrease in the short term (<30 days). Macroscopic and microscopic examinations revealed that spleen, liver, and kidney of the animals were normal, and the nitric oxide level of only liver tissues was significantly higher. In conclusion, the decoction extract obtained from B. chrysogonum tubers lowers the carbohydrate and lipid metabolism. The extract has no significant effect on the aminoacid and protein metabolism. The decrease in serum glucose, triglycerides, and cholesterol level may be attributed to reduced intestinal uptake of these metabolites. Triterpenoid saponins exist in the extract may reduce the metabolite absorption via altering membrane property of villi in the intestine. Daily instillation of the extract for 60 days did not have an adverse effect on the tissues examined and higher level of liver nitric oxide was attributed to increased blood flow in the livers. © 2005 Taylor and Francis Group, LLC.