Symptoms of Chinese restaurant syndrome usually begin within two hours after eating foods that contain MSG. They can last anywhere from a few hours to a couple of days. Common symptoms that you may experience include: 1  headache.2  sweating. 3  skin flushing. 4  numbness or burning in your mouth or throat. 5  nausea.ymptoms of Chinese restaurant syndrome usually begin within two hours after eating foods that contain MSG. They can last anywhere from a few hours to a couple of days. Common symptoms that you may experience include: 1  headache.