The first thing to consider is whether the bitterness of the mouth after meals is caused by abnormal diseases and infections in the oral cavity. You can first carry out oral care and examination, and promptly improve your living habits, carry out dietary control, reduce the intake of high-fat and high-cholesterol foods, reduce greasy, fried, spicy and stimulating foods, quit smoking and alcohol, and see if the symptoms improve. Secondly, we should further check the liver and biliary ultrasound as well as gastroscopy to see if there is any related biliary tract disease which causes bile reflux. Because bile is secreted in large quantities after eating, if the pylorus is relaxed, the bile secreted in large quantities may backflow into the stomach and thus into the mouth causing the corresponding symptoms of bitterness in the mouth. Then further examination will be conducted and if there is any related disease, appropriate treatment will be given. In addition, try not to lie down or sit still after meals, and it is recommended to get up and move around for about two hours. At this time, if it is due to bile reflux, it can effectively promote the bile to go down into the intestine instead of reflux, and see if it can relieve the corresponding bitter mouth symptoms.