Sudden vomiting and diarrhea is considered to be related to irritable bowel syndrome, acute gastroenteritis, acute food poisoning and cholera. 1. Irritable bowel syndrome: the etiology is not yet clear, may be related to visceral hypersensitivity, abnormal gastrointestinal dynamics, intestinal infections. Typical symptoms of patients include abdominal pain, diarrhea, constipation, etc. Sudden vomiting and diarrhea may occur due to increased mucus secretion in the colonic mucosa and disorders in the regulation of nerves innervating the colon. 2. Acute gastroenteritis: related to pathogenic microbial infection, improper diet, alcoholism and so on. Patients will have sudden vomiting and diarrhea symptoms, but also easily accompanied by abdominal pain, fever, loss of appetite, weakness, headache and other symptoms. 3. Acute food poisoning: mainly caused by the intake of food containing toxic substances, patients will experience nausea and vomiting, abdominal pain, diarrhea, dizziness, body weakness and other symptoms, can also be manifested as sudden vomiting and diarrhea. 4. Cholera: Cholera is mainly caused by Vibrio cholerae, which is mainly related to drinking contaminated water and ingesting contaminated seafood. Cholera can cause sudden vomiting and diarrhea, and it is easy to be accompanied by incontinence, hoarseness, dry skin and mucous membrane, hypotonia and other symptoms. Sudden vomiting and diarrhea is also considered to be related to acute bacillary dysentery and intestinal tuberculosis. It is recommended that the patient seek immediate medical examination in order to clarify the cause of the disease and then follow the doctor’s instructions for treatment.