Arm bruising means that there is bleeding under the skin of the arm, which means that blood is leaking out from the blood vessels to the outside of the blood vessels. For arm bruising to be cleared quickly, the specific cause of arm bruising should be clarified first. A trauma-induced arm bruise, the most effective method is to give local hot compresses, while taking bruising drugs, can quickly eliminate arm bruises. If the arm bruise is caused by allergic purpura, the most effective method is to apply vitamin C and glucocorticoid treatment. These two drugs can increase the density of capillaries and reduce bleeding, which can quickly eliminate arm bruises. In addition, if the bruising is caused by a coagulation disorder, such as vitamin K deficiency, vitamin K supplementation and, if necessary, plasma transfusion can also be given to quickly eliminate the bruising. For children or young people, who are prone to bruising after collision due to the blood vessel itself and no disease factors, they can eat more fresh fruits and vegetables to achieve certain effect.