Capillary bleeding generally has the following three causes: First, physiological reasons, many older people due to the physiological degeneration of capillaries, resulting in vascular brittleness, the lack of collagen tissue, will appear under the squeeze of a relatively minor force capillary bleeding, this situation is generally not heavy and does not require treatment, bleeding will soon stop, and is not easy to recur. Second, due to the lack of vitamin C resulting in insufficient collagen synthesis, capillary brittleness will increase, and rupture will easily occur under the slight force of squeezing or impact. Third, in hereditary capillary dilation, there are few supporting tissues around the capillaries, and the capillary walls are very thin, sometimes only a layer of endothelial cells. In this case, the capillaries are very prone to rupture and bleeding, and further laser treatment or other means are needed to control the bleeding.