THE ROBERT HO MAN KWOK LETTER, 4 APRIL 1968 Rob’s note: it took me longer than I expected to track down the text of Dr. Robert Ho Man Kwok’s infamous letter to the New England Journal of Medicine, which precipitated the anti-MSG movement. I republish it here for anyone else who is interested, to save them a similar journey. Rob Miller https://robm.me.uk/ Originally published: Ho Man Kwok, Robert. “Chinese-Restaurant Syndrome”. New England Journal of Medicine, vol. 278, no. 14, 4 April 1968, p. 796 nejm.org/doi/full/10.1056/NEJM196804042781419 ------------------------------------------------------------------------ CHINESE-RESTAURANT SYNDROME To the Editor: For several years since I have been in this country, I have experienced a strange syndrome whenever I have eaten out in a Chinese restaurant, especially one that served Northern Chinese food. The syndrome, which usually begins 15 to 20 minutes after I have eaten the first dish, lasts for about two hours, without any hangover effect. The most prominent symptoms are numbness at the back of the neck, gradually radiating to both arms and the back, general weakness and palpitation. The symptoms simulate those that I have had from hypersensitivity to acetylsalicylic acid, but are milder. I had not heard of the syndrome until I received complaints of the same symptoms from Chinese friends of mine, both medical and nonmedical people, but all well educated. The cause is obscure. After some discussion my colleagues and I at first speculated that it might be caused by some ingredient in the soy sauce, to which quite a few people are allergic. However, we use the same type of soy sauce in our home cooking, which does not result in the symptoms described above. Some have suggested that these symptoms may be caused by cooking wine, which is used generously in most Chinese restaurants, because the syndrome resembles to some extent the effects of alcohol. Others have suggested that it may be caused by the monosodium glutamate seasoning used to a great extent for seasoning in Chinese restaurants. Another alternative is that the high sodium content of the Chinese food may produce temporary hypernatremia, which may consequently cause intracellular hypokalema, resulting in numbness of the muscles, generalized weakness and palpitation. The Chinese food causes thirst, which would also be due to the high sodium content. The syndrome may therefore be due merely to the large quantity of salt in the food, and the high dissociation constant of the organic salt, monosodium glutamate, may make the symptoms more acute. Because we lack personnel for doing research in this area. I wonder if my friends in the medical field might be interested in seeking more information about this rather peculiar syndrome. I shall of course be more than happy to co-operate. ROBERT HO MAN KWOK, M.D. Senior Research Investigator National Biomedical Research Foundation