Phytotherapy (from the Greek words phyton, ie. plant and therapeuein, ie. care, heal) is an activity, also known in the past as herbalism, in which medicinal plants, mainly herbs (eg. chamomile, basil, lemon balm), semi-shrubs (eg. thyme, hyssop, lavender), shrubs (eg. blueberry, without, mistletoe), trees (eg. birch, oak, linden), also to a limited extent fungi and algae, etc. are used for the treatment of human. Phytotherapy is referred to as a kind of alternative medicine. A person practicing phytotherapy is referred to as a phytotherapist or herbalist. The first documented mention of the use of medicinal plants is from 3,000 BC from Sumerian clay tables. Over the past 20 years, there has been a growing interest in phytotherapy, and according to the World Health Organization (WHO), phytotherapy has been practiced three to four times more often than conventional medicine.