Most people will recover from mild cases of syndrome without treatment and with no lasting problems. But for those People who have experienced life-threatening reactions need to be extremely cautious about what they eat and should always carry medication prescribed by their doctor for emergency treatment.

MSG allergies also have a nickname 中華料理店症候群 (Chinese Restaurant Syndrome).
Due to in mid 60s, american experienced strange syndrome whenever they have eaten out in a Chinese restaurant, especially one that served northern Chinese food. The most prominent symptoms are numbness at the back of the neck, gradually radiating to both arms and the back, general weakness and palpitations, some might even have burning sensations, numbness, tingling, feelings of warmth, facial pressure or tightness, headache, nausea. All of the symptoms can simple explain by “overdose of vitamin b6.

In a double blind test, even the people who claim they are allegic to MSG show no reaction at all. As for one have reaction, 90% of those are american, while less than 2% are “asian”. During the test maxican, italian, japanese, chinese, and other cusine are serve(all of which cook with same amount of MSG) supricingly 98% show reaction only to chinese, none at others.
Finally only less than 1% of the one show reaction shown sign of life-threatening symptoms (similar to any other severe allergic reaction) such as shortness of breath, heart palpitations, chest pain, or swelling of the lips or throat, for which they require immediate medical attention.