What is the best treatment for foot swelling?

Swelling: It really depends on the cause. If its both feet and legs it may be due to congestive heart failure, low protein in the blood or chronic venous changes. You need a full evaluation by a doctor. The treatment depends on the cause. Sometimes elevation helps, other times medications are needed. Usually cutting back on salt intake is helpful also.

Depends on the cause: Some causes of swelling of the feet can include systemic problems such as hypertension, gout, and problems with the kidneys and localized issues such as arthritis, infection, lymphatic obstruction, blood clots, varicose veins, trauma (fracture, sprain, and tendonitis) and side effects to medication. Have it evaluated by a professional and get the appropriate treatment.