You can technically eat olives straight from the tree, but they are extremely bitter and unpalatable due to a compound called oleuropein. Raw olives have a very different taste and texture compared to cured olives, which are the ones commonly eaten. Because of their intense bitterness and potential contaminants from the outdoor environment, olives must be cured—usually by soaking in brine or other methods for several weeks to months—to remove the bitter compounds and make them edible. Eating raw olives straight off the tree is generally not recommended except for those who are accustomed to the taste, like olive growers. They are safe to eat but highly unpleasant in flavor without curing.