Bruises are usually caused by subcutaneous bleeding and are very common in daily life, and we often develop bruises on our limbs without realizing it. When bruising occurs, we can promptly apply cold and hot packs alternately. Within 24 hours of the appearance of the bruise, take the cold compress approach, cold compress 1-2 days later can be converted to hot compress. Hot compress can use hot water bag or hot towel for 10-15 minutes each time, 3-4 times a day, after 3-5 days, the color of local bruises will gradually become lighter, yellow, and slowly become normal color. The hot compress can expand the blood vessels on the surface of the skin, accelerate the local blood circulation, and accelerate the absorption of the bruise.