I was recently surprised to hear that the benefits of olive leaves in traditional and alternative medicine have mostly to do with anti-microbial activity. The leaf was used traditionally to treat all kinds of infections in areas where the trees naturally grow. Plagues still hit those areas, in years gone by. So, it is by no means a cure-all.
Modern research supports some of the traditional uses, because some fraction of the leaf inhibits the replication of viruses, bacteria and fungi. As a group, we usually refer to them as illness-causing pathogens.
