Bile is very important for the digestion of fats and elimination of certain toxic substances from the human body. It comes from the liver and it is commonly stored in the gallbladder in a form which has very high concentration. The bile flows through common bile duct and cystic duct in order to get to the duodenum. At the same time the food enters the duodenum through the pyloric valve. When the valve does not get closed properly the bile gets into the stomach and triggers irritation and inflammatory conditions. When the lower esophageal sphincter does not close properly, both the bile and the stomach acid get released into the esophagus.

This can cause inflammatory conditions, heartburn and it can also lead to certain other serious medical conditions. Bile reflux may be triggered by certain types of gastric surgery complications. The most common ones may include gastric bypass operations for weight loss and gastrectomy which involes the removal of the whole stomach. Peptic ulcers can also be the cause of bile reflux because they can lead to the blockage of the aforementioned pyloric valve which is located at the entrance to the duodenum. In this case the valve cannot open properly, and it leads to a significant increase of gastric pressure and the reflux of bile into the esophagus.

Long Term Risks
--Heartburn / Reflux / GERD - as previously mentioned, often this illness will also combine with acid reflux and allow the bile to make its way up into the esophagus. As the tissue within the throat is not meant to withstand acidity, this is the reason that the symptoms occur and can cause harmful effects when left untreated. 
--Barrett's Esophagus - the cells in the esophagus start to change color and may lead to malignancy. 
--Esophageal stricture (narrowing) - exposure to stomach acid may cause the lower esophageal valve to narrow and this may increase chances of choking or having trouble swallowing food. 
--Gastritis - irritation of the stomach leading to bleeding or ulcers. 
--Esophageal cancer - possible link due to the presence of acid in the throat.