Many causes and diseases can cause vomiting, usually due to gastrointestinal diseases, such as gastritis, gastric and duodenal ulcers, ulcerative colitis, etc. Gastrointestinal diseases are often accompanied by other clinical symptoms. Gastrointestinal diseases are not the only ones that cause vomiting, for example, seeing something dirty or smelling an unpleasant odor can also cause nausea or even vomiting. Vomiting can occur in early pregnancy in pregnant women, but it is a normal physiological phenomenon and a reaction to early pregnancy. The vomiting itself is a protective reflex and usually does not cause harm to the body. When the external cause of vomiting is removed or the disease is treated, the vomiting will stop. In addition, some food or drug poisoning can also cause vomiting symptoms, this situation should go to the hospital as soon as possible.