I have never eaten there that I haven't got sick, DH and 2 of the 3 kids as well. It's been over 5 years since I've eaten at one and have no plans to ever go again.
This is common for me as well, with Olive Garden and a few other restaurants that many others enjoy with no problems.
I have come to the conclusion that there is probably an oil or condiment that they use in all their food that simply does not... agree with me.

Honestly, I think it's an oil.
And in case I have not made myself clear, I don't want to describe what the food does to me because it's TMI

It's unpleasant and short lived and I can predict it.
Food borne illness symptoms and onset timing varies depending on the bacteria/virus/parasite involved.
I can't eat at Olive Garden, Ruby Tuesday and some very popular non-chain Mexican restaurants.
That doesn't mean that those places are not safe with food or serve "bad" food.
It means that my body cannot tolerate their food- other people have no problem with it.
These food sensitivities/intolerances can run in families.
My mother has the same issues, as do her sister and my cousins.
Yeah, we're a fun bunch

(but we're great cooks!

)
I am not trying to minimize your experience in any way.
Getting sick from food is getting sick and that is never fun.
Especially with kids
