Food poisoning, how long after you've eaten something does it start to take effect?

Guess whose running to the little girls room! Just wondering if it was my meal last night at friends house we had salmon, rice and veg stir fry or this lunchtimes fry up. Someone told me it took 24 hours to show symtoms but I'm blaming the fry up which I cooked 2 hours ago.Don't feel ill though.