The purpose of this study was to investigate the dose-dependent effect of Ankaferd Blood Stopper (R) (ABS) on the rat carotid artery model. Carotid arteries were removed and contraction/relaxation of isolated vessel rings were measured for dose-dependent epinephrine, papaverine and (ABS) administrations by a force displacement transducer. The data of each tissue specimen were collected with the use of a computerized system and corresponding software at a sample rate of 1000 kHz, and were expressed as contraction force. ABS is a standardized mixture of five plants, has been used historically as a haemostatic agent. Each plant extracts have different effects on the endothelium, blood cells, angiogenesis, cellular proliferation, vascular dynamics and cell mediators individually but ABS's mechanism of action remains unknown. In study, ABS has a vasoconstriction effect in low concentrations (5 and 10 mu L) On the other hand, ABS showed a vasodilatation effect in higher concentration (20-40-80 mu L). As a conclusion, haemostatic effect of this solution relies on mechanisms other than those related with vascular contractility, can be said.