Organ rejection is a fear for anyone who undergoes an organ transplant. Signs of rejection include pain, crankiness, fever, swelling, weight changes, and more. Sometimes the body mistakes the new organ for something dangerous. Immunosuppressant drugs are used after a transplant to prevent your body from attacking the new organ. There are ways to boost your chances of a successful transplant: wash your hands, avoid those who are sick, practice safe sex, and more. Follow the links below to find WebMD's comprehensive coverage about organ rejection after a transplant, how to treat it, and much more.