The authors investigated the microcirculatory bed in smoking patients with coronary heart disease (CHD) and evaluated a microvascular response to smoking. The findings suggest that cigarette smoking has a negative impact on the microcirculatory bed, causing pronounced spasms of arterioles and capillaries, a decrease in the number of functioning capillaries in 1 mm2 of the conjunctiva, an increase in intravascular red blood cell sludge, a reduction in blood flow, and appearance of stasis. In response to smoking, most CHD patients show worsening microvascular disorders appearing as not only a change in the diameter of microvessels, but also as enhancement of intravascular red blood cell aggregation.