Poultice preparations may be more commonly used in daily life to relieve bone, joint or muscle pain, and may be used in poultices or for other treatments. The fact that a poultice is itchy after it is applied cannot indicate that it is detoxifying. The itchy place on the plaster may be the occurrence of an allergic reaction, in addition to itching, there may be redness, burning sensation or other irritation, may be due to the allergic reaction occurred by the plaster. Once this happens, it is recommended that the patient remove the plaster and observe, and if the symptoms are more serious, go to the hospital. In conclusion, the itchy place where the plaster is applied cannot be said to be detoxifying, and must be observed for other discomforts. Patients with allergic symptoms, should minimize local stimulation, avoid scratching, should not use hot water scalding, avoid strong sunlight or hot wind stimulation. Keep the affected area clean and hygienic, eat more fresh fruits and vegetables to enhance the body’s immunity.