Anybody complaining of any of the following symptoms:

Heartburn, burning feeling in the chest
Nausea, vomiting, vomiting blood, Regurgitation, belching
Chest pain that increases after meals.
Difficulty in swallowing food, food sticking upon swallowing
Pain on swallowing food
Abdominal pain
Change in the bowel habits
Constipation
Diarrhea
Change in the shape or form of stool
Anemia, iron deficiency anemia
Blood in stool
Black tarry stool
Unexplained weight loss and loss of appetite

Any person above age 50:
As a screening test for colon polyps and colon cancer.
See the following link: "Are you above age 50"