Flavonoids are the chemicals in plants that give them yellow, red or blue color or pigmentation. Flavonoids are in many foods and are an important part of the medicinal qualities of food. Flavonoids are well-known to be anti-inflammatory, anti-allergic, anti-viral, and anti-carcinogenic. They are powerful antioxidants.
Foods that contain high amounts of flavonoids are: citrus fruits, red grapes, berries, onions, parsley, and beans. They are found in medicinal herbs such as green tea and St Johns Wort.
As we know gastrointestinal inflammation causes may of the symptoms of IBS such as stomach cramping, excessive gas and bloating. They reduce such inflammations. Calming intestinal inflammation will also reduce diarrhea and constipation. Quercetin, a flavonoid in onions and the herb St Johns Wort inhibits the release of histamine which is commonly elevated in IBS. People with irritable bowel should regularly consume foods and fruits that contain high amounts of flavonoids.