An anti-intoxicant was a medicine that allowed one to drink alcohol without experiencing the effects of intoxication.

In 2153, Doctor Phlox gave Captain Archer an anti-intoxicant so that he could withstand the effects of the Andorian ale which he was drinking with Degra, in an attempt to get Degra to give up information on the Xindi weapon. (ENT: "Stratagem")

In 2373, Benjamin Sisko and his infiltration team treated themselves with anti-intoxicants before attending the induction festivities for the Order of the Bat'leth, a celebration where copious amounts of Klingon bloodwine are traditionally consumed. Without the drug, Worf claimed that they would have been so drunk they wouldn't have been able to stand. (DS9: "Apocalypse Rising")