Took me a while to realise you were talking about 'Braindead'. Hilarious movie. Graphic as hell, but fucking funny, with some great one-liners, and perhaps the goriest 15-20 minutes in that lawnmower climax.
Oddly enough, though, the only scene I remember feeling genuinely nauseous in was when the fat, Australian (?) landlord (?? - can't honestly remember) is eating dinner, and right before he eats his pudding - custard, I think it was -the protagonist's mother's puss and rotting ear falls into his bowl. He then stirs it, and says something like, "Mmm, rich and creamy, just the way I like it." Funny, but fucking revolting all the same.