I'm looking for a natural cure.

Leg swelling is multifactorial but the most common causes are incompetent veins, protein malnutrition and congestive heart failure. There are many other diseases that can result in leg edema. Only a doctor can diagnose that, not people who think there is one cause and treatment for everything. The treatment very much depends on the underlying cause. If your doctor has told you to elevate them that suggests it is incompetent veins. Wearing compression stockings is also useful. Diuretics are not indicated if that is the cause of your swollen legs.

Tony I Copypaste's advice is once again detailed, simplistic and wrong as his "one true cause of all disease" mantra is that everything can be cured with diet, and ignores that edema may be a sign of serious underlying medical conditions.