The main causes of constant nausea and vomiting include pregnancy, gastrointestinal diseases, food poisoning and chemotherapy. 1. Pregnancy: If nausea and vomiting occurs in pregnant women, it can be considered as a normal physiological reaction during pregnancy, and usually does not require medical intervention, but if it is serious, it is also necessary to intervene. 2. Gastrointestinal diseases: such as acute and chronic gastroenteritis, gastroesophageal reflux disease, etc., may cause nausea and vomiting, and should be actively gastroscopy, followed by symptomatic treatment. 3. Food poisoning: can also cause nausea and vomiting, as early as possible hospitalization and symptomatic treatment. 4. Side effects caused by chemotherapy drugs: at this time, you can give, for example, metoclopramide antiemetic treatment. 5. Others: Nausea and vomiting can also occur when intracranial pressure rises. When the above symptoms occur, consult the hospital in time, complete the relevant laboratory tests to clarify the diagnosis and treat the symptoms.