Zhèng Xiāoyán 鄭肖岩 (1856–1934), zì Yánfǔ 巖甫, hào Yǐnjǐng Shānrén 飲井山人 (“the Recluse who Drinks from a Well”). Late-Qīng / early-Republican physician of southeastern Fújiàn (Fúníng prefecture, “海嶠”). Spent seventeen years compiling the original Wěi yào tiáo biàn 偽藥條辨 (1901) — a pharmacognostic monograph identifying about 110 drugs commonly counterfeited in the late-Qīng market and giving organoleptic criteria for distinguishing genuine from fake. The work was later expanded by Cáo Bǐngzhāng 曹炳章 as the Zēngdìng wěi yào tiáo biàn (KR3ec071, 1928). Zhèng’s postface to the 1928 expanded edition was written in 1917 when he was 69. Not in CBDB.