it s knowledge that dates back thousands of years the healing effects of plants and herbs knowledge that was hugely important in the middle ages but then to some extent forgotten. many scientists are now developing a curiosity for these plants and medical practitioners are rediscovering their healing powers. german herbs expert isla s fun put kama knows the healing potential of domestic plants here she s gathering herbs for medicinal teas some of the plan is. like metals and birch leaves because they flush out the urinary system and black berry leaves have an anti-inflammatory effect in the mouth. i use all 3 to make an herb and it s like a home pharmacy. to protect themselves against pests and pathogens herbs often can. oils bitter substances and acids that kill germs