钱乙专精儿科逾40年，创立以五脏为纲的儿科辨证体系，所创「六味地黄丸」（原为治小儿肾怯之方）后被历代医家广泛借用于成人肾阴虚证，流传至今。其弟子阎孝忠将其临证经验整理成《小儿药证直诀》，是中国现存最早的儿科专著，钱乙也因此被后世尊为「儿科之圣」。

Qian Yi specialized in pediatrics for over forty years and established a five-organ pattern-differentiation framework for treating children. His formula Liuwei Dihuang Wan, originally devised for pediatric kidney deficiency, was later widely adapted by physicians for adult kidney-yin deficiency and remains in common use today. His student Yan Xiaozhong compiled his clinical experience into the Direct Instructions on the Patterns and Treatments of Children's Diseases, China's earliest surviving dedicated pediatric text, earning Qian Yi the title "Sage of Pediatrics."