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


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                     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