Terminalia arjuna (TA) is a medicinal plant used as a cardiotonic in ayurveda. Besides others, scientific evidence dictates its strong hypolipidemic and antioxidant properties. However, anti-inflammatory and antiplatelet aggregatory properties of TA are not known. The present study demonstrates in vitro effects of its ethanolic bark extract (TAE) on platelet function indices. Twenty patients of angiographically proven coronary artery disease (CAD) were included in Group I and 20 age and sex-matched controls were included in Group II. Platelet activation was monitored by determining P-selectin (CD62P) expression, intracellular free calcium (Ca(2+)) release and platelet aggregation. In vitro effect of TA on platelets function indices was determined by incubating the platelets with TAE in a time and dose-dependent manner in presence/absence of ADP. TAE was able to significantly inhibit platelet aggregation both in patient and control groups. Significant attenuation in Ca(2+) release and expression of CD62P was also observed with TAE. Our data clearly demonstrates that the bark extract of TA decreases platelet activation and may possess antithrombotic properties. The possible mechanism of action could be by desensitizing platelets to the agonist by competing with platelet receptor or by interfering with signal transduction. Thus, TA can be exploited for its therapeutic potential in CAD and related cardiovascular disorders.