Horace N. Allen, an American physician, was a Presbyterian missionary to Korea. In 1886, he wrote the annual report of the Korean government hospital, summarizing patient statistics according to outpatient and inpatient classification for the first ever in Korean history. In the report, he speculated that hemoptysis cases of outpatient might have been mainly caused by distoma. Allen’s conjecture was noteworthy because only a few years lapsed since the first scientific report of paragonimiasis. However, he was not sure of his assumption either because it was not evidently supported by proper microscopic or post-mortem examinations. In this letter, we thus revisit his assumption with our parasitological data recently obtained from Joseon period mummies.