Herxing is what happens when you kill pathogens. They release endotoxins which enter the bloodstream and make one ill until they exit the body. It was named after the researchers who discovered this action, I believe around the 1930's, Jarish-Herxheimer. Sometimes when a person kills off a lot of pathogens at once the herxing makes one feel worse than the pathogens did. Some feel flu-like symptoms and I feel neuro symptoms which are very hard to bear.