Bad oral hygiene can lead to sour taste. Excess use of tea, caffeine, cocaine and tobacco can cause sour mouth. Injuries to nerves or brain can lead to sour taste. If you are suffering with depression, stress disorders or anxiety, it may also be a cause of sour taste in the mouth.
Health conditions. Certain health conditions can cause symptoms of flatulence, including: 1  indigestion. 2  constipation. 3  irritable bowel syndrome (IBS) â a common digestive condition, which can cause stomach cramps, bloating, diarrhoea and constipation. 4  coeliac disease â an intolerance to a protein called gluten, found in wheat, rye and barley.
Swallowed air rarely is the cause of excessive flatulence. The source of excessive gas is intestinal bacteria. The bacteria produce the gas (primarily hydrogen and/or methane) when they digest foods, primarily sugars and nondigestible polysaccharides (for example, starch, cellulose), that have not been digested during passage through the small intestine.