A person with IBS has an increased reactivity and sensitive digestive system so that the gastrointestinal tract reacts differently to normal gut stimuli, such as the passage of solids, fluid and gas through the intestines. These uncommon movements may lead to difficulty in passing stool.Individuals may have different combinations of symptoms that interfere with their life.Abdominal pain or discomfort is the main characteristic of IBS and is often poorly localized and may be migratory and variable. It may occur after a meal and can last for hours. Those with IBS have a faster and more intense reaction to digestive tract pain stimuli than who do not have IBS.In addition to pain and discomfort, altered bowel movement are common, including diarrhea, constipation or both. IBS has different categories depending on stool consistency. IBS-D (diarrhea): the digestive system contracts and transits products of digestion quickly, leading to frequent watery bowel movements. IBS-C (constipation): the digestive system contracts and transit products of digestion more slowly, leading to difficulty in passing infrequent stools. IBS-M: a patient has a mix of both diarrhea and constipation due to alter in transit time throughout the digestive tract. Prolonged contractions of the bowel might prevent the normal passage of air and cause bloating, belching, abdominal distension and flatulence. Bloating could become so severe that clothing feels tighter and abdominal swelling becomes noticeable to others.Patients with irritable bowel syndrome also complain of mucus in the stool, insistence, and a feeling of incomplete evacuation. Patients often report symptoms of other functional gastrointestinal disorders such as heartburn, chest pain, difficulty swallowing, nausea or dyspepsia, or a sensation of a lump in the throat or closing of the throat. Another symptoms that are unassociated to the intestine are common in patients with IBS and may include a headache, sleep disturbances, post-traumatic stress disorder, temporomandibular joint disorder, sicca syndrome, back/pelvic pain, myalgias, back pain, and chronic pelvic pain.Some people can control their symptoms by managing diet, lifestyle and stress. More severe symptoms can be treated by medication and counseling.Some patients with moderate to severe IBS start feeling a poor quality of life (QOL) due to multiple symptoms that are more frequently and intensely. This low quality of life could make the person feel like not doing her normal routine. Also, mood disorders are a complication of IBS. People with IBS frequently suffer from the signs and symptoms that can lead to depression and anxiety which also can make IBS worse. That’s because the colon is in part controlled by the nervous system, which responds to stress. It was reported that approximately 10-20% of adults in Western countries have IBS symptoms and as well as the similar prevalence has been reported in AsiaGlobally, Southeast Asia has the lowest prevalence of IBS (7.0%) and South America the highest (21.0%). Unfortunately, the incidence in Africa is not clear due to a few population-based studies. More studies are needed in the countries that lack detailed epidemiological data.the prevalence in medical students and interns in King Abdulaziz University, Jeddah was 31.8% in 2013, with a female gender, anxiety, incidence of emotional stress, living in a school dormitory away from the family and the advanced academic year were showing the main predictors of IBS.