Guided by the theory of latent pathogens， it is believed that the basic pathogenesis of adult-onset Still's disease is the latent pathogens in the deep yin level. The onset of the disease is fundamentally characterized by the deficiency of both qi and yin as the root， with dampness， heat， phlegm， and blood stasis as the branch， which triggered by intruding pathogens activate the latent pathogens in yin level. The treatment focuses on nourishing yin and dispersing heat as the key therapeutic method. It is proposed that clearing and resolving dampness-heat， expelling pathogens outward， dispersing the latent pathogens， reinforcing healthy qi and consolidating the root， boosting qi and nourishing yin as treatment idea. In clinic， Qinghao Biejia Decoction （青蒿鳖甲汤） could be used as the basic formula， and modified with characteristic herb pairs such as Qinghao （Artemisia annua） - Digupi （Lycium chinense） to enrich yin and clear heat， and enforce the power of clearing deficient heat； Biejia （Lawsonia inermis） - Xuchangqing （Vincetoxicum mukdenense） to enrich yin and activate blood， unblock the collaterals and dissipate masses； Duhuo （Angelica biserrata） - Mudanpi （Paeonia × suffruticosa） to dispel wind and activate blood， resolve dampness and unblock the collaterals， so as to clear and warm simultaneously， and regulate qi and blood at the same time； and Chuanshanlong （Dioscorea nipponica） - Difuzi （Bassia scoparia） to dissolve stasis and dispel phlegm， explore and dispel latent pathogens.