Modern medicine has transformed our lives and wellbeing, but some ancient remedies still have a place in our hi-tech hospitals. Sean Fletcher is in Hendy, south Wales, visiting Europe's most productive leech farm, which supplies 70 per cent of medicinal leeches worldwide. He joins for feeding time and discovers how these often-reviled three-jawed creatures are making a comeback, helping patients recover from trauma or severe infections. Leeches aren't the only creepy crawlies with a place in modern medicine. In Swansea, Sean discovers how maggots are working their magic for a patient recovering from a major infection. And we meet Dr Christina Lee, who is taking a fresh look at remedies going back 1,000 years.Sean also dips into the Countryfile archive to explore nature's medicine cabinet in our countryside, and he looks into warnings that veterinary medicine in Northern Ireland is being overlooked, posing serious consequences for animal welfare and the economy.