If the edema is mostly in one leg, it is recommended to have it checked by a doctor since it can be a health issue that would benefit from a particular treatment.
Edema in the leg is often linked to a poor venous circulation but then the swelling is equal in both legs, unless you had an injury to the main veins in your left leg.
When one leg swells up more than the other it is often linked to the lymphatic system and can be caused by a variety of issues. The first step is to have the doctor look at it and make a diagnostic.
When you know exactly what it is, contact me and I will be able suggest some natural ways to help you. Meanwhile make sure you drink a minimum of 2 litres of water a day.
Edema can be a sign of dehydration. Also avoid salt as much as possible since it can be a major cause of edema.