Hot salt water is possible to reduce swelling, but need to be divided into circumstances, if the time of application is not right or some swelling, will make the symptoms worse. If the trauma caused local subcutaneous hematoma, in the local stop bleeding two days after the local hot saline compresses, will promote the absorption of subcutaneous hematoma, but also can promote the tissue exudate reflux. If the lymphatic drainage is slow, applying hot saline compresses locally can also promote the swelling to subside. However, if the local swelling is caused by infection, it is not possible to use hot saline compresses, which will lead to the spread of infection and aggravation of the swelling, which requires a visit to the hospital, the use of antibiotics, and if necessary, surgical treatment. And also in the newly injured swelling can not be used, this will aggravate the subcutaneous blood seepage, so that the swelling is more serious.