5 year old boy vomiting food (Macaroni/Cheese) from Thursday. Has eaten since (eggs, bacon, spaghetti). Stated his stomach hurt and then vomited. He just finished a 5 day round (Tuesday) of steroids, and 10 day supply of antibiotic (Augumentin) for a severe sinus infection. States his stomach still hurts. Should I be concerned?

He is reclining, took few sip of 7Up and bite of saltine cracker.

Have you phoned your child's pediatrician? Our pediatrician or a physician assistant is always on-call.

No, not yet. They are only open M-F... office hours. I wasn't sure if I should take him to the ER or wait to call the dr. on Monday.

I can't comment on the effects of steroids, but can on antibiotics. I have had too many conditions in my life that required heavy doses, such as Lyme and cellulitis. I didn't do enough to eat carefully, long afterwards. Studies have shown that in children, good intestinal bacteria take many months to recuperate, and some don't for as long as 2 years. I might be able to find the file if you want. The foods you are feeding him are difficult for a compromised digestive tract to handle. I would avoid cheese and bacon, for starters. Yogurt and chicken broth and rice would be better than 7up and Saltines. Avoid any form of sugar if you can help it, even fruity yogurts, but if you have to to get him to eat it, go ahead.
Doctors rarely talk about, or even know about, how to eat after antibiotics. Sad

It's also quite possible he has the stomach flu that is going around right now. 7up and saltines are goog for that.

Make sure he is not suffering from dehydration. Making sure his eyes are lubricated, his lips aren't dry or chapped and that he is urinating regularly.

Thank you everyone for the answers. They really help. He is feeling better today... no more vomiting.

Thanks for letting us know. The first link here is the most alarming:
The Wired Atlas of the Human Ecosystem | WIRED
Antibiotics: Killing Off Beneficial Bacteria ... for Good? | WIRED