i'm allergic to bullshit Share definition Flag just another way to say that you don't believe what someone says. came from a line in "I,Robot". 1: I did that hot girl last night! 2: *sneezes* Oh sorry dude, I'm allergic to bullshit. i'm allergic to bullshit by KRHimself October 9, 2004 0 0 Get merch Get the i'm allergic to bullshit mug. Buy Now — $32.95 See more merch