Castor oil, a vegetable oil from the castor oil plant, can be used on feet for its anti-inflammatory, antifungal, and moisturizing properties. It can help reduce pain and swelling, combat fungal infections, and soften dry skin. However, safety precautions should be taken to avoid skin irritation and allergic reactions, especially during pregnancy and breastfeeding. Castor oil can be mixed with carrier oils or used as a thick cream directly on the affected area.