Post Orgasmic Illness Syndrome
In rare cases, men may experience flu-like symptoms such as fever, runny nose, headaches and nausea after ejaculation. The symptoms can last for weeks. It’s called post orgasmic illness syndrome, and it’s an autoimmune response in which the body recognizes its own semen as foreign and attacks itself. Dr. David Josephson, a urologist, says that symptoms can begin immediately or hours later, making it difficult to diagnose.