Comfrey in the form of a poultice for external application is a remarkably effective treatment for wounds that do not heal, such as decubitus ulcers (bedsores), diabetic ulcers, the bites of brown recluse spiders, and the terrible staph infections that affect people living on tropical beaches. All of these conditions can produce large, open lesions that resist the strongest pharmaceutical treatments. Use the root of the plant, which you can buy dried in bulk from many herb suppliers. Grind it to a powder in a blender, and mix the amount you need with water or even better, with aloe vera gel to make a paste. Gently pack it into the wound and cover with a bandage. Change the poultice once a day, washing out the wound with water and with hydrogen peroxide if any infection is present.