is there any pairs of food which can cause death if eaten together?

Answer 1

One possibility is that both foods contain essentially the same ingredient and doubling its dose will be even more toxic (vodka and rum).
Another possibility is the ingredients react with each other releasing a dangerous product. Example: Mentos and Coca-cola.
I can imagine that there may be some exotic pairs of food with one having a mildly toxic ingredient, which normally could be neutralized (e.g. oxidized in liver); and the other containing an inhibitor of the detoxifying enzyme (so that the first one cannot be neitralized). This is well-known for drugs, but I do not know the examples among common food items.

Answer 2

I almost killed myself by eating grape nuts breakfast cereal each morning and drinking a full-octane (not diet) mountain dew two hours later, almost every day. In a few months, my triglycerides went up to over 600. Diabetes + heart trouble would have been fast on the heels if not for a lot of niacin, canned beans and tunafish over the next 3 months.

Allergic reactions to food happen most often (it seems to me) when an allergenic food is eaten with a protein-rich meal, as opposed to a carbohydrate meal.

I ate a Waffle House omelet in which they stir a bunch of that overcooked soy oil into the eggs and I thought I was going to die.

Answer 3

a Chicago hot dog and catsup - will cause an angry mob to jump on you - you might not die if you can run fast enough

Answer 4

Yes.

Green eggs and ham.

Answer 5

Yes. Liver and onions. ;-)

Answer 6

no way