Swelling of the right foot may be due to the following causes: 1. It may be caused by injuries around the right foot, such as sprains or direct violent blows to this area, which may cause soft tissue contusions or fractures here, resulting in very obvious swelling of the right foot due to subcutaneous bleeding and sterile inflammation here. 2. It may be caused by long-term pressure, such as the right foot 3. It may be caused by circulatory system-related pathologies, such as deep vein thrombosis in the right lower extremity or obstruction of the lymphatic vessels in the right lower extremity, such as filariasis, which may cause swelling of the right foot. 4. Infection in this area, such as bacterial infection or fungal infection for the foot may exist here, both of which can lead to a very obvious swelling in the infected area.