Trombodipine is an antithrombotic agent. Exposure to 50 μM Trombodipine reveals an important stasis of growth. The percentage of inhibition exerted by 1 μM Trombodipine on day 3, 5 and 7 of the growth curve is 22.0±4.5, 32.0±3.0 and 29.4±6.0%, respectively (P<0.05). The inhibitory effect of Trombodipine on cell proliferation is reversible and after removal of Trombodipine the proliferation of the cells is resumed. Addition of Trombodipine reduces cell number in a dose-dependent manner over a period of 4 to 6 days in culture. When compare to control cultures at the latest time points investigated, 5 μM Trombodipine decreases the number of E19P cells and human VSMCs by 25 and 21%, respectively, whereas 50 μM Trombodipine reduces E19P and human VSMC number by 85 and 74%, respectively.