 Flavonoids are widely found in plants and diets, have various bioactive effects, and their basic structures consist of C6 and hashtag X2713, and hashtag X2713, and hashtag X2713 rings with different substitution patterns. However, their poor bioavailability limits information about associations between structure and biological fate, which this review aims to address by bringing order into relationships between structure, activity, and pharmacokinetics of bioactive flavonoids. This article was authored by Tianyang Wang, Qingli, and Kaishan Bai.