In biofeedback, a machine is used to measure skin temperature and other responses. By watching the machine a patient can learn to control muscle tension and blood pressure. Amazing results have come from the use of feedback, which has been successful in treating headaches, muscle pain, and even drug addition. Homeopaths treat disease by giving a patient tiny amounts of a remedy that would produce symptoms similar to those of the disease in a healthy person. In Europe, this treatment has been known to help patients with flu, headaches, and allergies.