It most commonly involves abnormal biliary tract peristalsis muscular coordination within the gallbladder in response to dietary stimulation of that organ to squirt the liquid bile through the common bile duct into the duodenum. Ineffective peristaltic contraction of that structure produces postprandial (after meals) right upper abdominal pain (cholecystodynia) and almost no other problem. When the dyskinesia is localized at the biliary outlet into the duodenum just as increased tonus of that outlet sphincter of Oddi, the backed-up bile can cause pancreatic injury with abdominal pain more toward the upper left side.