Edema, commonly known as swelling, can have various causes. Some common causes of edema include: Prolonged standing or sitting: This can lead to fluid accumulation in the legs and feet. Certain medications: Some medications can cause fluid retention as a side effect. Injury or trauma: Swelling is a common response to injury. Heart failure: When the heart doesn't pump effectively, fluid can accumulate in the body. Kidney disease: Impaired kidney function can lead to fluid retention. Liver disease: Conditions like cirrhosis can cause fluid buildup in the abdomen and legs. Pregnancy: Edema is common in pregnant women, especially in the legs and feet. Malnutrition: Protein deficiency can lead to edema. Infections: Inflammation due to infections can cause localized swelling. Allergic reactions: Some allergic responses can lead to edema.