I have a very vague memory of a movie that was probably released in the 1980’s. In it the main character visits a rural town where the townspeople gradually go crazy, acting of character and increasingly violent.
The main character isn’t effected because it turns out the local milk supply has been contaminated and he doesn’t drink it.
‘The Crazies’ sounds like it has a similar premise but I’m pretty sure its not it.
Please tell me I didn’t just imagine this movie!
I think it’s Impulse (1984) with Tim Matheson and Meg Tilly
I’m pretty certain you’re right! Thank you 
That was a great movie.
Any movie with Meg Tilly is great, by definition.
34 minutes in the middle of the night.
Boo-ya.
Enough about your sex life! 
The critics disagree. (Interesting that some of the reviews mention the only good thing is Tarantino’s cameo. When a Tarantino cameo is the highlight, it’s that bad of a film.)
I don’t remember the movie, but I wonder whether it was inspired by the true story of le pain maudit (“the accursed bread”). In the 1950s the inhabitants of the small French village of Pont-Saint-Esprit started hallucinating and acting strangely. Several people died, between 4 and 10 depending on who you ask. The outbreak was eventually traced to the bread from one bakery in town, but to this day no one really knows what was in the contaminated flour that caused the symptoms. Theories include ergot, LSD, unapproved bleaching agents, and unapproved fungicides.
Despite already being answered this sounds like the plot of two different movies starring Wings Hauser and Bo Hopkins that I watched on RiffTrax.
“Mutant” is about two guys who drive into a small rural Midwest town to get their car fixed and find the locals are becoming increasingly violent due to a chemical from a nearby waste treatment camp seeping into the water supply.
“Nightmare at Noon” is about two guys who drive into a small rural Southwestern town to get their RV fixed and find the locals are becoming increasingly violent due to a chemical put into their water supply as part of a Government funded Black Ops experiment.
welp there goes mu suggestion. I would have guessed the romero original, not the remake, btw
I think you’re actually looking for Bitter Harvest (1981), starring Ron Howard. In it, Ron plays a dairy farmer who’s herd gets sick and starts dying, and the local townspeople also start acting bizarrely and getting sick. It turns out the cattle feed company also made fire retardant containing Polybrominated biphenyl, and the stuff was accidentally mixed in with cattle feed and made its way into the milk supply. It’s based on a true story.