Hé Yóu 何游 (zì Dànān 澹安, CBDB 263567) — Jiāngnán physician of the early-to-mid nineteenth century in the Sūzhōu / Wúzhōng post-Yè Tiānshì 葉天士 (葉桂) clinical tradition. He is conventionally identified with the Hé family of Ménghé 孟河 in Jiāngsū — one of the four principal Ménghé medical lineages (Fèi 費, Mǎ 馬, Cháo 巢, Hé 何) systematically reconstructed in Volker Scheid’s Currents of Tradition in Chinese Medicine 1626–2006 (Eastland Press, 2007). Some sources identify him as the elder of the Hé brothers, but the genealogical data are not secure and his exact lifedates are unknown. His casebook is KR3ep005 Hé Dànān yīàn 何澹安醫案. CBDB records the name but no dates.