Luomen Kan is a secondary character in The Apothecary Diaries. He is a disowned member of the La clan, a eunuch physician formerly serving the Inner Court, and later an apothecary in the capital's red‑light district. He is also the adoptive father, mentor, and paternal great‑uncle of the protagonist, Maomao. His background is marked by tragedy: while serving as the imperial court physician, he was forced to attend to the simultaneous births of the former emperor’s son and Ah‑Duo’s son Jinshi. Despite his protests, he was ordered to prioritize the imperial son, and during the chaos a switch was made that saved Jinshi but led to the real imperial brother’s death, which was actually caused by Fengming feeding the infant poisoned honey. Luomen was blamed, severely beaten, had a kneecap removed, and was exiled from the palace. The La clan also disowned him for the dishonor. After his exile, he settled in the red‑light district, where he ran a small pharmacy and took in Maomao, raising her and teaching her both Eastern and Western medicine. He is a gentle, kind‑hearted man who shows deep care for his patients and for Maomao, despite his own suffering. His motivations stem from a genuine desire to heal and help those in need, and he never seeks revenge for the injustice done to him. Later in the story, the inner court reluctantly recalls him to assist with the complicated pregnancies of consorts Gyokuyou and Lihua. He succeeds in delivering the crown prince and is eventually reinstated as court physician, though his exile is never formally apologized for. His key relationships include Maomao, whom he raised and taught all his medicinal knowledge; Lakan, his nephew, who was also exiled for being close to Luomen and whom Luomen had earlier helped learn to recognize people by mentally mapping them as shogi pieces; and Lahan, Lakan’s adopted son, who becomes a close ally. Luomen’s notable abilities include his genius in both Eastern and Western medicine, his deep knowledge of herbs and poisons, and his calm, methodical approach to diagnosis and treatment. He is also a resilient figure who endures great personal loss and physical injury without bitterness, focusing instead on serving others. His development is seen in his quiet acceptance of his past while gradually reclaiming his place in the palace, and his role is essential in shaping Maomao’s skills and independence.