Objective:To observe the toxic effects of Tripterygium wilfordii extract on chronic heart injury in rats.Method: Sprague-Dawley rats were administrated and randomly divided into four experimental groups:control group

low dose group

middle dose group

and high dose group of T.wilfordii（17

34

68 mg·kg-1 accordingly

by gavage）for 90 days.On the 0th

15th

30th

60th and 90th day after administrated

the electrocardiogram

serum potassium and heart function were tested.The pathological changes were evaluated by Haematoxylin-eosin（HE）.Result: There was no changes in electrocardiogram

serum potassium and heart function of the rat in low dose group compared with that of the control group.But in the middle dose group

on the 60th day

Q-T interval

S-T interval

QRS interval was prolonged

heart rate decreased significantly

S-T segment changed significantly compared with those of the control group.While potassium was decreased

left ventricular systolic pressure（LVSP）

maximum slop of left ventricular pressure（±dp/dtmax）was significantly reduced

and the left ventricular end diastolic pressure（LVEDP）was increased significantly（P<0.05）.The high dose group had the similar changes with the middle group on 15th day after administrated（P<0.05）.The middle dose and high dose of the T.wilfordii extract could induce significant pathological changes of rat heart compared with that of the low does group and the control group.Conclusion: The middle does and the high does of T.wilfordii extract could induce significantly cardiac injury

and pathological changes of cardiac muscular tissue.But low dose has no obvious toxicity for heart.