Fisetin, a natural flavonoid found in various fruits, vegetables, and nuts, has various biological properties, including anti-inflammatory, anti-oxidant, neuroprotective in cell culture and in animal models relevant to human diseases. Fisetin can be also a promising agent for the treatment of uveal melanoma. Besides, it is a therapeutic agent for respiratory inflammatory diseases such as chronic obstructive pulmonary disease (COPD), where fisetin inhibits the TNF-α-activated IKK/NF-κB cascade by targeting PKCδ. In vitro and in vivo experiments have revealed that fisetin possesses significant therapeutic effects against diabetic complications and atherosclerosis, where it can suppress vascular inflammatory processes.