Bird's nest is a nest created by swiftlets from their solidified saliva. After collection, processing, feather removal, and impurity removal, it has been a valuable food since ancient times, used by emperors as a precious ingredient for beauty and wellness. In traditional Chinese medicine, bird's nest is believed to nourish Yin and moisten dryness, replenish qi and strengthen the middle burner, and benefit the stomach and spleen. According to "Ben Cao Gang Mu Shi Yi" (Compendium of Materia Medica Supplement), bird's nest is described as "sweet, bland, and neutral in taste, greatly nourishing lung Yin, tonifying yet clearing, a sacred medicine for treating deficiency, consumption, and emaciation."