Yes IBS can cause nausea infact im the worlds worst nauseated ibs sufferer ( well it feels that way ha ha) It doesnt normally make you sick but yes a food intolerance or allergy can make you this way - I also have anxiety and this makes me very nauseated too.
Try cutting dairy out of you diet for a few weeks and see what happens - im currently omitting dairy too so we can do it together lol. xx

jenz,
Do you get restless or nervous when you get nauseated? I feel like a hose at the gate getting ready to race!
I also ate lettuce a couple of days before I got sick and the time before that I ate dairy.
Do you also get bad acid indigestion?
I hate being that way!

yes hun i get all of this too - i cant eat lettuce and i try and cut out as much dairy as i can. Ask your doc for stuff for the indigestion i in the uk and i take opermozal ( not sure if spelt right ) and its fab stuff !!!

I've gone gluten and dairy free but still struggling with IBS-C. Lettuce aggravates my IBS as does peanuts, and most nuts and seeds. I also get nauseous just before a BM and sometimes get an achey/acid stomach at the same time. Belching has just become a way of life.

It's pretty common for people with IBS to have these symptoms. I know I get them when I eat foods that disagree with my stomach. My route is to avoid medications and take herbs, natural products, supplements and vitamins. As well aroma therapy oddly enough can help. I was just having some stomach upset myself about an hour ago, it was causing me to have anxiety. So I drew a hot bath, threw in some magnesium salts (epsom salts) some aroma therapy oils (lavender, eucalyptus, etc.) and I managed to calm down pretty well.
If the bloating, gas, etc are bothering you, try some fennel seed tea, camomile tea or my fave, lavender tea.

I get nausea almost every day.. I take what's called gravol.. although I found out some people in the US don't know what that is.. it's for motion sickness.. that usually helps.. sometimes I do throw up too.. I am following a strict IBS diet from Heather Van Vorous.. who wrote a book "IBS: The First Year" This eliminates dairy, caffeine, greasy food, red meat and anything else that's tough to digest.. although it has helped my pain.. I still get nauscious. I would try eliminating dairy, red meat and processed foods as much as possible first. goodluck, hope you feel better.

dairy irritates IBS, as well as any food with fat content. I have been trying to eat just these things: applesauce, plain couscous(cooked with chicken stock), and Bird's Custard made with soy milk. I am feeling a little better, so I think I might have figured out my triggers.
I can't stand the nausea, bloating and painful gut area.

YES!!! I have all of that and Nausea all the time! I hate it.