Hu Sihui (Chinese: 忽思慧, 和斯輝, 忽斯慧, also Hu Zheng Qi Huei; active nr. 1314–1330) was a court therapist and dietitian during Yuan Dynasty reign in China. He is known for his book Yinshan Zhengyao (Important Principles of Food and Drink), that became a classic in Chinese medicine and Chinese cuisine. He was the first to empirically discover and clearly describe deficiency diseases.
The career of Hu Sihui, as he states in preface to his book, was in the reign of Buyantu Khan in Yenyu years (1314—1320). An ethnic Mongol, and an official in Xuanhui Yuan (the Ministry of Court Supplies and Provisions), around 1315 Hu Sihui initially emerged as the therapist of Empress Dowager, soon also became the therapist of the acting Empress, and later received the rank of the chief Imperial therapist and became responsible for food and drinks of the numerous Emperor's family.
As tradition has it, Buyantu Khan, after several years of expeditions and irregular life, was overstrained and suffered acute pain in his kidneys. The vegetable soup prescribed by Hu Sihui cured the pains in 3 months, and one of Emperor's spouses became pregnant. The Emperor grandly awarded Hu Sihui as the cause of this "double joy".
In 1330 Hu Sihui, no longer busy with the Emperor and his harem, completed and presented to the Court his book Yinshan Zhengyao (饮膳正要), summarising the experiences of the court dietitian. The main idea of his work was that people preparing food for the Emperor are directly responsible for efficiency of the State, as a monarch may get sick from improper eating, and lose ability of managing state affairs.
Yinshan Zhengyao states that a significant number of diseases is caused by improper eating, and a significant part of them can be cured by proper eating. The book propagated moderation, regularity and variety in food, proper hygiene and food storage, and special diets for pregnant women and for children. This book was the first to describe in detail how diseases are connected to deficiency of certain components in food. It was probably the first book in China to dwell on food poisoning.
Recipes presented show strong Han Chinese as well as Mongolian, Turkic and Persian influences. As Hu Sihui states, a large variety of foods were known in the court since Kublai Khan and this novelty needed special research as to its influence on health. Taken as a collection of recipes and ingredients alone, his book is a tremendously important description of Medieval food of Eurasia.
The section of recipes starts with a variety soups, barley, then noodles and breads. Many recipes represent Central and West Asian cooking traditions, roughly translated into Chinese categories, some even translated from Turkic languages.  Two examples of recipes are:
- Wolf Soup: Wolf meat (leg: bone and cut up), tsaoko cardamom (three), black pepper (five chien), kasini (one ch’ien), turmeric (two ch’ien), za’faran (one ch’ien). Boil together into a soup. Adjust flavors of everything using onions, sauce, salt, and vinegar.
- Deboned Chicken Morsels: clean, cook, and cut up ten fat chickens, debone as morsels, juice of sprouting ginger, onions, ginger, Chinese flour, pepper, make into vermicelli 
Hu Sihui's book was widely accepted in Later Yuan, but won even wider influence after the fall of Yuan. Ming Dynasty, after occupying Beijing in 1368, started to combine Chinese cuisine from other regions with the cosmopolitan cuisine of Yuan court. Jingtai Emperor of Ming (ruled 1449—1457) personally wrote a preface to an edition of Yinshan Zhengyao.
As a culinary encyclopedia, this book made some regional recipes aссepted as part of national cuisine of the whole of China. For example, it is this book that contained a recipe of a roast duck that could be a predecessor of the widely known Beijing Duck.
- Buell, Paul, Eugene Newton Anderson, Hu-ssu-hui. A soup for the Qan. Chinese Dietary Medicine. Kegan Paul International, 2000. 715 pages. ISBN 978-0-7103-0583-1
- Husihui, Paul D. Buell, E. N. Anderson, et al., A Soup for the Qan Chinese Dietary Medicine of the Mongol Era as Seen in Hu Sihui's Yinshan Zhengyao: Introduction, Translation, Commentary, and Chinese Text (Leiden: Brill, 2nd rev. and expanded, 2010).
- Françoise Sabban, "Cuisine À La Cour De L'empereur De Chine: Les Aspects Culinaires Du Yinshan Zhengyao De Hu Sihui," Médiévales (1983): 32-56. 
- Jack N. Losso; Fereidoon Shahidi; Debasis Bagchi (2007). Anti-angiogenic functional and medicinal foods. CRC Press. p. 102. ISBN 1-57444-445-X.
- Needham, Joseph. Poverties and Triumphs of the Chinese Scientific Tradition. \\ In: The "Racial" Economy of Science. Indiana University Press, 1993. ISBN 0-253-20810-6, ISBN 978-0-253-20810-1 – page 41 on discovery of deficiency diseases
- Unschuld, Paul Ulrich. Medicine in China: A History of Pharmaceutics. University of California Press, 1986. ISBN 0-520-05025-8, ISBN 9780520050259 pages 213—214
- Allsen, Thomas T. Culture and Conquest in Mongol Eurasia. Cambridge University Press, 2001. ISBN 0-521-60270-X, 9780521602709 стр. 130—131
- Husihui, Paul D. Buell, Eugene N. Anderson, tr., A Soup for the Qan: Chinese Dietary Medicine of the Mongol Era as Seen in Hu Szu-Hui's Yin-Shan Cheng-Yao: Introduction, Translation, Commentary and Chinese Text (London; New York: Kegan Paul International, 2000. ISBN 0710305834), p. 169.
- Hu Sihui, A Soup for the Qan p 295.
- Imperial Food in the Ming Dynasty на сайте China Internet Information Center
- "Beijing Duck". International Chinese Language Council website. China Internet Information Center. 2008. Retrieved 2008-10-17.
- "北京特產 (Specialties of Beijing)" (in Traditional Chinese). Xinhua. 2004-04-08. Retrieved 2007-09-10.