Is medicinal marijuana doing good or harm? It has been called a miracle, lifesaving medicine. But is it as safe as it’s cracked up to be? Politicians from across the aisle in Canberra and in the states are moving to trial medical marijuana. But many aren’t waiting for clinical tests. A growing movement of parents are using it to control kids’ epilepsy and adults are using it to manage chronic pain. This week, Insight cracks the lid on where medical cannabis comes from, what’s in it, and what it’s doing to patients. Host Jenny Brockie speaks to the suppliers – who come from areas as far afield as Nimbin and suburban Sydney – about the 'science' behind their 'miracle drugs', and the legal risks they face by providing it. Parents and patients speak about their success in using marijuana for a range of illnesses, and their desperation to have it legalised. But Brockie also hears from medical experts who believe there's no proven medical benefit to using marijuana, and that those using it are at risk of mental health issues. As the prospect of legalisation and clinical trials looms in several states, Insight also asks whether legal marijuana will lead to an increase of recreational use – and just what will happen to the black market.