Onion for knee pain is generally not true. Onion as a food has no therapeutic effect, do not use indiscriminate prescription to avoid delaying the formal treatment. There are many reasons for knee pain, such as calcium deficiency, bruises, overwork, infections, rheumatism, rheumatoid, etc. Patients with knee pain should not blindly use medication. Patients with knee pain should not overwork, pay attention to rest, pay attention to keep warm, if the knee pain is caused by calcium deficiency, usually eat foods with high calcium content, such as milk, beans, sesame paste, eggs, etc.. If you have knee pain symptoms, you need to go to the hospital as soon as possible, the doctor according to the specific conditions, to develop individualized diagnosis and treatment plan, so as not to delay the condition.