Large, painful bumps on the outer side of the soles of the feet can be caused by corns, plantar warts and boils, which can be treated with medication, physical therapy and surgery. 1. corns: corns can be caused by long-term pressure and wear and tear, and can be treated by applying salicylic acid ointment or corns ointment under the guidance of a doctor, or through physical therapy such as freezing, laser, and so on. 2. Plantar warts: Plantar warts are caused by human papilloma virus infection and can be treated by applying topical retinoic acid ointment. 3. Boils: Boils are mainly caused by poor plantar hygiene and can be treated by applying 2% fusidic acid cream under the guidance of a doctor, or surgically when the patient is not sensitive to the medication. Patients should choose the appropriate treatment under the guidance of the doctor’s advice, in the use of drugs, should follow the doctor’s instructions, do not remember to take private, in order to avoid adverse effects.