For brushing teeth always nausea, the reasons are as follows: 1, toothbrush too far to the throat, etc.: when brushing teeth, toothbrush too far to the throat, can stimulate the throat to produce reflexes, and nausea. Toothpaste contains more aromatic agents, such as mint, or toothpaste produces a lot of foam, can also stimulate the mucous membrane of the throat to produce vomiting. 2, chronic pharyngitis: thickening of the mucous membrane of the throat, more secretions, brushing a large amount of liquid blocking the throat and produce stimulation, will trigger vomiting. 3, early pregnancy: this time women are prone to nausea and vomiting symptoms of toothbrushing, as a normal manifestation of pregnancy reaction. 4, digestive tract Diseases: When suffering from gastric ulcer, duodenal ulcer and other digestive tract diseases, acid reflux often occurs, which causes nausea and vomiting.