Nausea from headaches (migraines, especially), and from menstrual cramps, I am well acquainted with. I've also been mildly nauseated from dislocating my knee last summer, though that may have been just the fact that I felt it both dislocate, then pop back into place on its own. Grossest feeling ever.

Nausea from toothache was a first. It wasn't intense, just a mild sicky-sick feeling in the pit of my stomach. Just enough to think "Hey, I don't feel so great...".