Extracts of root bark, stem bark and the latex collected from the green fruits of Garcinia mangostana gave alpha-mangostin, beta-mangostin, gamma-mangostin, garcinone-E, methoxy-beta-mangostin and a new geranylated biphenyl derivative 3-hydroxy-4-geranyl-5-methoxybiphenyl. The latex of G. mangostana consists of more than 75% of xanthones which have strong antibacterial (anti-MRSA and -VRE), anti-inflammatory, antifungal and a number of other biological activities. Hence the presence of the above highly bioactive compounds in large quantities should be the causative factor for G. mangostana's medicinal value in indigenous medicine.