Objective: Effects of platelet aggregation and thrombin time in vitro in rabbits by water extracts and volatile oil from Olibanum and Myrrha and their compatibility were studied to evaluate their effect and dose-effect relationship. Method: Extracts and oils from Olibanum and Myrrha and their combination in different compatibility on platelet aggregation induced by adenosine diphosphate(ADP) in vitro

thrombosis by using thrombin time (TT) method and their dose-effect relationship were observed. Interaction effects of two drugs used in compatibility were measured by an isobole method. Result: The results showed that all the extracts and their combinations in different compatibility had significant or very significant inhibitory effects on the platelet aggregation induced by ADP. Compatibility of the extracts had synergism effect and its activity was better than both single-use of extracts. The experimental data of TT indicated that different extracts from Olibanum and Myrrha could all significantly prolong clotting time of blood plasma in rabbits. Except that combination of water extracts of Olibanum: Myrrh (1 ∶1) had antagonism effect

the others had synergism effect. Conclusion: Water extracts and volatile oil from Olibanum and Myrrha and their combinations in different compatibility all showed significant effect in vitro on platelet aggregation and thrombin time in rabbits. Furthermore

except that compatibility of water extracts of Olibanum: Myrrh (1 ∶1) had antagonism effect

the other showed synergistic action. The study provided reference for scientific characters and rationality of herbal compatibility.