Background To investigate the benefits of adjunctive Chinese herbal medicine (CHM) for patients with nasopharyngeal carcinoma (NPC). Methods We included all patients diagnosed with NPC during 1997‐2009 and followed until 2011 in Taiwan. We used 1:1 frequency matching by age, sex, comorbidity, conventional treatment, and index year to compare the CHM users and non‐CHM users (n = 2542 each). The prescribed CHM was further investigated with regard to its cytotoxicity. Results Compared with non‐CHM users, adjunctive CHM users had a lower hazard ratio of mortality risk, and a better survival probability. Gan‐Lu‐Yin (GLY) was the most commonly prescribed CHM, and it reduced cell viability, inhibited tumor proliferation, and induced apoptosis through the poly (ADP‐ribose) polymerase and caspase‐3‐dependent pathway in human NPC TW01 cells. Oral administration of GLY retarded NPC‐TW01 tumor growth in the xenograft nude mouse model. Conclusion Real‐world data and laboratory experiments implied that adjunctive CHM might be beneficial for NPC patients.