A new Laser-Doppler microvelocimetering (LDMV) was developed to study blood flow in individual vessels in patients with coronary artery stenosis. The LDMV measures steady blood flow velocity, diameter of vessels and pulsation flow. In addition, the effects of China's traditional herbs--Salvia Mitiorrhyza and other drugs--on the blood flow in the patients were investigated. LDMV constitutes a new quantitative procedure and is a promising tool for rapid monitoring of tissue perfusion in cardiovascular disease and estimating the action of drugs on microcirculation.