When should i see a doctor for an upset stomach? what kind of doctor should i see?

Primary care: Basic symptoms of upset stomach, like diarrhea, heartburn, constipation, abdominal pain, nausea or vomiting, can be evaluated and treated by a primary care doctor. Symptoms of heartburn can be treated at home with Tums or Pepto Bismol. Mild diarrhea can be treated with Lomotil (diphenoxylat and atropine) or Kaopectate. Bloody diarrhea, a fever, or severe symptoms that last more than 24 hours = a trip to the doctor.