What is the reason for my bitter mouth in the morning?

The mouth is very bitter in the morning, there are two common reasons: the first is that the patient recently eats more dry food, so that the liver fire in the body is caused; the second is seen in digestive tract diseases, most common in reflux esophagitis, which is a disease caused by the reverse flow of stomach and duodenal contents due to abnormal anti-reflux barrier in the body.