The Allergy Ghosts are the manifestations of supernatural infections planted in potato chips.
Doctor McCatheter supplied the Ghostbusters with New Spirit Chips under the guise they were health food. In reality, they were supernaturally tainted chips designed to influence an allergy to ghosts when large amounts were consumed. The Ghostbusters forced their bodies to build up an immunity by locking themselves in Janine's Apartment with Slimer.   Eventually, the guys fully transformed and the allergies were literally trapped right off them.
- ↑ Egon Spengler (2009). The Real Ghostbusters - "Something's Going Around" (1989) (DVD ts. 19:31-19:36). Time Life Entertainment. Egon says: "Unless we force our bodies to build up an immunity to this allergy."
- ↑ Egon Spengler (2009). The Real Ghostbusters - "Something's Going Around" (1989) (DVD ts. 19:39-19:49). Time Life Entertainment. Egon says: "In forced exposure. To wit, we lock ourselves in a room with a highly concentrated source of ectoplasmic energy and let nature take its course."