The Nutty Professor (1963) features the "Alaskan Polar Bear Heater", a drink invented by the lead character and dictated to a barman. Although Buddy drinks it without any noticeable effect, the barman takes a sip and loses consciousness.
In Back To The Future III, "Authentic Frontier Whiskey" is strong enough to cause the bar to smolder. Doc, who Can't Hold His Liquor anyway, downs a glass and drops like a brick at the most inconvenient time. Also, when they try to fuel the DeLorean with some of the bartender's strongest whiskey, it blows the fuel manifold out of the ass of the car!
Quint gives Brody a glass of something he made himself in Jaws. Brody can't handle a sip of it without spitting it out, and tells Hooper not to drink it. Hooper downs it anyway, and merely coughs, so maybe Brody is just a lightweight.
The Disney flick Condorman has the title hero (a comic book writer pretending to be a CIA agent) order an "Istanbul Express" for a Russian spy he's trying to impress — and a double for himself. The waiter, shocked, says, "Nobody orders a double!" He promptly makes it a triple. As a spoof of the trope, the drink is actually served on fire, resulting in a hilarious Fire-Breathing Diner scene.
Another Disney flick, Snow Dogs, features "soup", which is stored in a hip flask. When questioned about the quotation marks, the maker replies, "Well, there's soup in it."
Revenge of the Nerds. Another Alpha Beta brother asks Stan Gable to try a drink called simply "Fireball". He has one sip straight from the bottle and promptly spits it out all over. As it turns out, it has a ridiculously high proof, and Haystack later spits it through a lighter's flame and burns down the AB house.
Bartlett: In the three years, seven months, and two weeks that I've been in the bag, that's the most extraordinary stuff I've ever tasted. It's shattering! MacDonald: (mildly) Well, I think it's rather good.
The French movie Les Bronzés font du ski has an iconic scene (itself inspired from a similar one in a theater play by the same actor team, Le Père Noël est une ordure) involving a Gargle Blaster. Since they got themselves lost in the mountains, the protagonists are given shelter by local villagers. After a Masochist's Meal, they are offered a drink that is described as "shallot liquor". Inside the bottle is a large toad, with a lovely description of how it was dehydrated before being put inside. "You gotta drink it fast, else it stings the tongue." When they finally (and very reluctantly) try out the beverage, the effects are varied. One of the protagonists immediately faints; another gets red-faced and burst into tears; a third one starts coughing violently because his mouth is burning; the last one find it rather tasty.
It's not alcohol (probably) but Wednesday and Pugsley make some rather fiery lemonade when they try to make money selling it in The Addams Family. When they give a free sample to Lurch, he feels some discomfort for a minute after drinking it, then breathes fire, scorching a wooden statue of an Indian. (Then he just shrugs and continues on his way.) Sadly, we never see a scene where they sell any to an actual customer.
The Matrix. Whatever Cypher gives to Neo that makes him gag.
Cypher: Good shit, huh? Dozer makes it. It's good for two things, degreasing engines and killing brain cells.