A nervous stomach is not an official medical diagnosis, but it often refers to a stomachache caused by physical ailments or emotional stress, explains WebMD. Bacteria and viruses can produce an upset stomach that may result in nausea and vomiting, and stress and anxiety can cause intense stomachaches or cramps.
Emotional and mental stress, excitement, and anxiety can make people feel nervous and queasy, which results in a stomachache, according to WebMD. Individuals with social anxiety may experience nervousness and a butterfly feeling in the stomach before the first day of school or a new job, whereas performance anxiety may produce a stomachache before a meeting, sporting event or stage performance.
Stress and fear can also cause people to feel nervous and experience physical pain in the stomach, explains WebMD. A new experience, financial worries or conflicts with friends or families can cause an upset stomach. Overexcitement during a big event or milestone, such as a wedding or graduation, can also increase the risk of developing stomach ailments.
Physical ailments often attributed to a nervous stomach include indigestion, bloating, changes in bowel habits and nausea, according to Mayo Clinic. Physicians who are unable to find an underlying disorder, such as an ulcer or gallstones, for the stomach pain may label the ailment as a nervous stomach or attribute the pain to excess gas.