The specific reasons for nausea and vomiting are not clear, but after clinical research, it is considered to be related to the change of hormone levels in the body, especially chorionic gonadotropin and estrogen, which indirectly stimulate the gastrointestinal tract causing a decrease in gastric acid secretion and relaxation of gastrointestinal smooth muscle, resulting in weakened gastric peristalsis and prolonged gastric emptying time, so that food cannot be fully digested and stays in the stomach. This causes gastric distension, nausea and vomiting, and the symptoms will generally be reduced after 3 months of pregnancy. There are also causes of eating too much caused by poor digestion, gastrointestinal dysfunction caused by bloating, nausea, vomiting, long-term stomach discomfort, nausea, can not exclude chronic gastritis, inflammation stimulates gastric mucosa congestion, mucosal secretion of gastric acid dysfunction caused by indigestion, easy to cause food retention, fermentation caused by nausea, vomiting, can first improve dietary habits, eat less and more meals, chew slowly, semi-liquid diet, etc.