Bioflavonoids were once known as vitamin P and are also considered semi-essential nutrients that are responsible for the color of fruits and flowers. They are used in the treatment or prevention of various diseases. There are four categories and these are the proanthocyanidins, quercetin, the citrus flavonoids and green tea polyphenols. The major sources of these bioflavonoids are from plants. The bioflavonoids are known for their antioxidant activity but a great number of other bioactivities are also attributed to them. Some of these bioactivities will be presented as well as the bioactivities of the rare flavonoids isolated from Syzygium samarangense (Blume) Merr. & L.M. Perry. Plant natural products, arguably, will still play a major role in providing the world with an alternative and a more effective health care.