Thanks for the query. Stomach upset has the varied etiology might be due to infection, food poisoning, indigestion, constipation. Foods that contain sulfur include poultry, red meats, dairy products (specially milk),vegetables (asparagus, broccoli, watercress, yams, cabbage, onions, pack choi, mustard, parsley, onions, sweet potatoes. The most serious and common cause are Helicobacter Pylori or Giardia. Helicobacter Pylori is a bacterium that causes chronic gastritis, gastric ulcers, abdominal bloating. Some of the recommended foods to eat to get rid of sulfur burps include plenty of fresh vegetables and fruits. If there is fever, vomiting, loose motions, signs of dehydration then see a doctor. Hope i helped you.