Swelling can occur after a ligament strain. The pathological mechanisms of swelling caused by ligament strains are mainly as follows: 1. While the ligament strains occur, some small blood vessels around the ligament will rupture, which will produce some internal bleeding around the strains, which is the mechanism of swelling in the early stage. 2. After the ligament strains, a series of sterile inflammation will be rapidly produced around the ligament, and the inflammation will lead to fluid exudation around the ligament, which will produce swelling afterwards. 3, Since most ligaments are located in the more inferior parts of the extremities, due to the drainage of body fluids, that is, the effect of gravity, body fluids will gradually accumulate inside these newly created gaps, which in turn leads to swelling. After the ligament strain produces swelling, take ice cold as soon as possible, then use elastic bandages or braces and so on to fix the injury site, and then assist some anti-inflammatory, anti-swelling, pain relief drugs for treatment. Only in this way can the swelling be reduced as quickly as possible, and prevent the swelling from continuing to increase.