Olive leaf tree is one of the most common, traditional herbal teas used among Mediterranean people to cure certain diseases. The phenolic compounds present in olive leaves, especially the oleuropein, are associated to antioxidant, antihypertensive, hypoglycemic, hypocholesterolemic and cardioprotective activity. Many olive oil producers even charge a fee to the olive farmer for the disposal of olive leaves. In current study, some of these studies on the beneficial health effects, antioxidant, antimicrobial and phenolic compounds of olive leaves are reviewed.