Approximately 20 million Americans will develop an ulcer over their lifetimes, the University of Maryland Medical Center reports. These open sores form on the inside lining of your gastrointestinal tract -- along the esophagus, stomach or small intestine.

Indigestion, gas and bloating are common symptoms that have a variety of causes, including the consumption of certain foods. Baking soda contains sodium bicarbonate, the active ingredient in some antacid medications.

Gentle home remedies such as peppermint tea and ginger root are common herbal treatments for upset stomach. Although symptoms may differ slightly from person to person, spicy foods can cause indigestion as well as irritation of the stomach lining.

Ginger holds an almost mythical place among natural remedies, particularly with digestive disorders. And science backs up ginger's effectiveness for some of these digestive issues, including morning sickness in pregnancy, nausea and motion sickness.

Numerous conditions can cause left flank pain, or pain on the left side of the torso. According to the Clinical Methods website, flank pain is a sensation of pain or distress in the part of the torso between the ribs and the ilia, or hip bones, and the upper abdomen and back.

The appendix is a small finger-like organ attached to the large intestine. When a blockage occurs in the appendix, bacteria begin to grow and an infection develops, also referred to as appendicitis.

Vitamin D is essential for your immune system and bone health, and if you do not get an adequate amount in your diet, you may need to take a supplement. However, because vitamin D is fat-soluble, your body stores the excess, which can lead to a toxicity if you take too much.

The proteins casein and gluten are two of the top allergens found in the American diet, the former being found in dairy products and the latter in many grains. Some digestive enzyme supplements containing the enzyme DPP-IV, or dipeptidyl peptidase-4, can facilitate the breakdown of these offending proteins.

According to the University of Maryland Medical Center, right-sided flank pain may be caused by direct trauma, problems with the abdominal organs and other medical conditions.

Milk of magnesium, also known as milk of magnesia, is commonly used to reduce the amount of acid in your stomach and is used to treat constipation, but it may also cause stomach pain as a common side effect of as a result of an overdose.

Certain medical conditions can give a feeling of fullness without eating a single bite of food. This typically occurs with conditions related to your stomach and liver. Other conditions, such as gallstones or gallbladder disease, can make you feel full after only a few bites of food.

If you have loose, watery stools more than three times a day, you have diarrhea, as defined by MedlinePlus, a service of the U.S. National Library of Medicine and National Institutes of Health. Treatment of diarrhea varies and depends on the cause.