Potato slices on bruises can take up to 5 days to recover. Human bruises are caused by the rupture of capillaries in the case of trauma, which can cause swelling and pain. Potatoes contain a lot of starch, which is hypertonic and can treat fluid exudation and relieve swelling; they also contain many B vitamins, which are beneficial for the recovery of inflammation; in addition, potatoes contain alkaloids, which have the effect of activating blood and relieving pain. Therefore, in general, potato slices are suitable for bruises within 48 hours and are more effective. It has no toxic side effects of drugs, and is simple and economical, safe and reliable. However, it is only suitable for light bruises, and its recovery is slow, about 5 days at the earliest. If the patient is accidentally injured skin damage, it is recommended to first take ice to relieve the pain. Then you can cut the raw potatoes into slices and put them on the injured part, change them every 15 minutes or so, about four times a day, for five days, and if they do not improve, you should seek medical attention.