Joining this thread late, but know this:
Food allergies can cause nausea and vomiting and abdominal pain.
It’s called GI anaphylaxis and it’s a true IgE-mediated allergic reaction, and it can be quite severe.
I couldn’t see this link because it required membership - did it say what sorts of foods I should avoid? I really am not interested in a repeat performance! 
Damn, now I can’t read the link either. WTF?
Basically avoid the foods you’re allergic to. If Macadamia nuts cause the symptoms, stay away from them. But allergy to one tree nut doesn’t mean one has allergies to other tree nuts. See your doctor to see if specific allergy testing is right for you.
I don’t get macadamias-they are loaded with fat, and are just about tasteless.
Almonds cost less and have some tatse.
But macadamias? Like chewing parrifin wax.
Your experience is not universal. Many folks, including myself find them delicious.
De gustibus non est disputandum
My allergy tests showed me to be allergic to fresh fruits and vegetables but nothing at all on nuts (don’t know if it included macadamias or not) or seafood, which I’ve also had the same reaction to at times. Once it happens, I don’t eat that food again but I’m starting to run out of things I can eat… :dubious:
Best discuss further with an allergist, if you’re running out of things to eat. I believe macadamia nuts can be specifically RAST tested for.
I, for one, would worry if you did do puking well.
The good news is that, on having encountered an actual macadamia nut tree, I can report that getting the nut out of its husk and then it’s shell is really hard. Like, roll in the hydraulic press, hard.
So, you are unlikely to accidentally swallow a macadamia out in nature.
We receive a big tin of macadamia nuts every Christmas. It’s from a client of someone who used to own our house. We used to forward them but after years we stopped, and just started eating them. My wife and I have both ended up queasy after indulging too much. They taste great, but they are pretty greasy. I think it’s just too much fat at one sitting.
Agree. I have a stunted macadamia tree in my kitchen. It drops lots of tiny nuts all over the floor. They look like slighly large mouse turds. Can’t crack 'em open but they have reseeded just fine. Obviously, with the size of them they are not nuts for consumption. I was so hoping they would be when I was given the tiny tree. Now I just keep it for novelty’s sake. I will donate it to a conservatory sooner or later.
Oh, I’m not going to get within 10 feet of a macadamia nut again! I just wish that when I get tested and come up negative for something, it STAYS negative! :smack:
Heh, most people do puking much better than I do. I’ve done it maybe four times my adult life and each time I had a lot of trouble getting it done. I must have a very strong gag reflex or something, because it isn’t just opening my mouth and spewing, it involves what feels like every muscle in my body, a lot in the way of dry heaves and pain.
Well that’s a relief! 
Allergies can indeed cause vomiting as a symptom. Dweezil had a pretty rough evening a year or so back - we were at dinner with a large group of people in a restaurant in Arizona. He was sitting away from me, near Typo Knig, and ordered something with mole sauce. Neither of them realized that mole often contains peanuts.
OOPS!!!
The 15 minute drive back to the hotel took most of an hour, as we kept stopping to give him the opportunity to hurl (he didn’t do so but sure wished he could have). Finally an hour or so back at the hotel, he did throw up and felt much better.
Others in the group who had the mole were fine, so it wasn’t food poisoning. I called the restaurant later on and confirmed that it did indeed contain some peanuts. Lesson learned by Typo and Dweezil, at a far lower cost than it might have been.
BTW - macadamias are also often cooked in coconut oil, so it’s worth figuring out which of those is the culprit.