Warts are caused by a virus and any recurrent infection may be a sign that your immune system is beleaguered. Common warts, however, are notoriously difficult to get rid of. In order to strengthen your immunity, make sure you’re eating a healthy diet of fresh, unprocessed foods and avoiding sugar and alcohol. Deficiencies in vitamins A and C and zinc reduce the immune system’s strength, so take a good antioxidant or multivitamin. Various natural substances are recommended for putting directly on the warts to get rid of them: a thin slice of garlic, aloe vera gel and vitamin C cream (or a paste made from vitamin C powder). You can buy the latter two from your healthfood shop. Viruses have a hard time surviving in a vitamin C-rich environment, so I’d start with that one.