From the perspective of evidence-based medicine, internal salt intake cannot reduce swelling, but will instead increase sodium and water retention and increase the degree of edema; however, external sodium chloride can have a dehydrating effect on swelling. Excessive intake of sodium chloride in the usual diet can increase the concentration of crystalline osmolality in the body and increase water intake, leading to sodium and water retention and increasing the degree of edema, so by taking salt orally can not reduce swelling, but will increase the degree of edema. However, if the external ice saline wet compresses joint sprain swollen parts, due to the adsorption of sodium chloride, can make the tissue dehydration and play a role in swelling; mosquito bites parts of the swelling can also be used saline wet compresses and play a role in swelling. So salt can play a role in swelling when used externally, and internal use will aggravate the degree of edema.