Abstract: Aim To study the effects of aspirin (Asp) and verapamil (Ver) alone or in combination on mesenteric microcirculation of rats. Methods Acute microcirculation disturbance (AMD) was produced by highmolecular weight dextran (Mr 480,000) 360 mg·kg^-1 iv. A rteriol and venul blood flow velocity and diameter (ABFV, VBFV, AD, VD) and blood flow state (BFS) were observed by intravital microcirculation method. Results Asp 2.5, 5 mg °kg、Ver 0.3,0.6 mg·kg、Asp+ Ver (1+0.15),（2.5+0.3) mg·kg^-1 iv significant increase ABFV by 11.1 %, 31.3%, 18.7%,19.5%,26.5%,37.3%, VBFV by 12.5%,5.7%, 2.5%,3.7%,30%, 34.7%, AD by 4.3%, 17.9%, 31.5%, 35%, 20%, 38.1% and VD by 2.2%, 4.2%, 25%, 31.5%, 5.8%, 23.5% espectively, and got a raise in the number of capillaries and a marked improvement of BFS. Asp+ Ver(1+0.15, 2.5+0.3) mg·kg^-1 iv could reverse AMD. Conclusion Asp is superior to Ver in the increase of BFV, but Ver is superior to Asp in expansion of blood vessel. Asp in combination with Ver produces marked synergistic action and protection againist AMD

Key words: aspirin, verapamil, combination drug therapy, microcirculation, blood flow velocity