Phytotherapy involves the use of plants for their restorative properties. These are attributed to certain plants' production of phytochemicals like polyphenols, alkaloids and terpenoids. There is a branch of phytotherapy called phytoembryotherapy that strictly uses the plants' embryological tissues, such as buds and young shoots. This is due to the fact that many of the beneficial compounds - including phytochemicals - no longer exist once chlorophyll is formed in the plant.