Sweet taste in the mouth may be caused by diabetes, infection, gastroesophageal reflux disease, neurological disorders and other reasons. 1. Diabetes mellitus: disorders of glucose metabolism occur, which is an endocrine disease, and most of them will feel sweet in the mouth. Insufficient insulin secretion in diabetes affects the ability to control blood glucose, elevating the level of sugar in the blood, which leads to a sweet taste in the mouth. 2. Infection: Bacterial infections interfere with the brain’s response to taste when they affect the airways. Infected sinuses can cause too much glucose to be secreted in the saliva, leading to a sweet taste in the mouth. 3. Gastroesophageal reflux disease (GERD): A metallic or slightly sweet taste in the mouth. Stomach acid can reflux back into the esophagus and then into the mouth, resulting in a sweet taste in the mouth. 4. Neurological disorders: When the nerves are damaged, it can cause a constant sweet taste in the mouth. For example, epilepsy with stroke and seizures can cause impaired consciousness, affecting the senses of smell and taste. It is recommended to seek medical treatment.