In so doing, Yen has led Taiwan into a new era in disease and drug-use prevention. Yen began his career as an internist and has continued to make use of his medical training since taking up government service. When Taiwan was hit by SARS in 2003, he established Taiwan's first fever-screening station at the clinic he was then running.
本身為內科醫生，棄醫從政的顏純左充分發揮所長，2003 年 SARS 襲台時期，仍在經營診所的他設立了國內第一個發燒篩檢站而展現遠見。