"Toxic brew" refers to a dangerous or harmful mixture of things or situations. It symbolizes a combination that creates a negative or harmful effect, similar to poison in liquid form. Full definition
That's when everything that you used to enjoy, tolerate, or dislike about someone blends into the same toxic brew and you don't even remember why you liked them in the first place. (sbnation.com)
Onions and garlic can turn around a bland dish, but Indian biotechnologists have found another use for these roots: filtering heavy metals from toxic brews. (discovermagazine.com)
A: Picture that scene in old horror movies where a mad scientist holds up a bubbling beaker full of some strange toxic brew. (health.com)