At what point should I take my 11-year-old with a stomach bug to the doctor?

Asked by gimmedat (3951) January 31st, 2009 from iPhone

The poor guy is on day 5 of exploding from both ends. He doesn’t have a fever, no blood in his stool, and has been able to keep liquids down. He continues to complain of a stomach ache, though, and cannot keep food down. The pain is not in the lower right so I’m pretty sure it’s not the appendix. But, he’s still miserable. I’m convinced he’s got the full on flu, and that as long as he’s hydrated and doesn’t run a fever, it’s just got to run its course. Am I way off base?