To observe the toxicity of the water extract of the Mongolian medicinal herb Carthamus tinctorius L.(HS) to the liver，heart，and kidney.Methods:Rats were intragastrically administrated with low-，medium-，and high-dose HS water extracts once a day for 3 months.Blood was collected from the tail once every 14 days.The serum levels of glutamic-pyruvic transaminase(GPT)，glutamic-oxalacetic transaminase(GOT)，triglycerides(TG)，lactic dehydrogenase(LDH)，creatine kinase(CK)，urea，and creatinine(Cr) were determined.Three months later，the rats were sacrificed and the liver，heart，lung，kidney，spleen，stomach，intestine，and brain were collected.Hematoxylin-eosin(HE) staining was employed for the observation of pathological changes.Results:The serum levels of GPT，GOT，TG，LDH，CK，Urea，and Cr and the tissue sections showed that the three months of treatment with low-，medium-，and high-dose HS water extracts basically did not cause injuries in the liver，heart or kidney.Conclusion:The administration with HS water extract within 0.476 7～8.580 6 g/kg for three months has no toxic or side effect on the liver，heart，and kidney.