Yáo Sēngyuán 姚僧垣 (zì Fǎwèi 法衛, 499–583), native of Wǔkāng 武康 in Wúxìng 吳興 (Zhèjiāng); eighth-generation descendant of the Sūn Wú-period scholar-official Yáo Xìn (Grand Constant). The senior court physician of the Liáng, Western Wèi, and Northern Zhōu dynasties — one of the most celebrated medical authorities of the sixth century. He served in succession under Liáng Wǔdì, Jiǎnwéndì, Yuándì (Liáng); during the Hóu Jǐng rebellion he abandoned his family to rescue the Liáng emperor; later transferred to the Western Wèi court at Chángān after the fall of Liáng (552), and continued through the Zhōu Wéndì, Wǔdì, and Xuāndì.
His principal work, the Jíyàn fāng 集驗方 (KR3ed113, reconstructed text), in 12 juǎn, was widely circulated in the Sui and Táng and a major source for the Qiānjīn yàofāng and Wàitái mìyào. He also wrote a Xíngjì 行記 (“Travelogue”) and a Jiǎnyào fāng 减要方 (now lost).
Yáo’s biography in Zhōushū 47 records his famous case of correctly diagnosing the Liáng Wǔdì’s fatal high fever, when his recommendation against the dàhuáng (rhubarb) purgative was ignored with fatal consequence — a cause célèbre of physician-court relations in early-medieval medicine. He was honoured with the title Bēipínggōng 沛平公 under the Zhōu. His son Yáo Zuì 姚最 (zì Shìmóu 士謀) is the Xù Huàpǐn author and continued the medical tradition.