Pyrogen

Any substance that causes fever when it enters the body. Endotoxin from Gram-negative bacteria is the most common and potent, but non-endotoxin pyrogens also exist. Injectables deliver pyrogens straight into the bloodstream, so parenteral products are controlled through endotoxin testing and, for some products, pyrogen or monocyte activation tests, and glassware is depyrogenated by dry heat. Japanese documents also use the katakana loanword for pyrogen.