This product is for the treatment of common warts and verrucas. Common Wart: Common warts have a raised 'cauliflower-like' appearance and are skin coloured, hard and rough. They usually occur on fingers, the backs of hands and the knees. Verruca: Verrucas are more flattened, have hard outer edges and often have small black spots in the centre. They occur on the ball of the foot, the bottoms of the toes, or on the heel. A single treatment may be sufficient however, for verrucas, additional applications may be required.