Michael Stoopman shows his neck where he had a large cancerous ulcer , and five months where the area is healed .
" If I ' m prescribing something I really need to understand it and the more I learn about it , the less I know ," Dr Lacey said .
" It ' s quite a complex drug or herb and it ' s got a lot of nuances in to how to prescribe it . " People assume that cannabis is one product and it ' s actually a really complex collection of plants and species of plants ."
Each cannabis plant has up to 100 different cannabinoids , which are chemical compounds found in marijuana plants .
Dr Lacey said science was still learning about the potential medicinal effects of each cannabinoid .
" There are multiple strains and there are multiple cannabinoids within each strain and you need to have the right drug for the right indication for the right person ," she said .
She said she was optimistic science would soon discover lots of new medicinal uses for cannabis .
" I think this is a really exciting time in medical history ," she said .
Doctors ' uncomfortable ' with cannabis
The training program has been organised by medical cannabis advocate Lucy Haslam .
" Australian doctors don ' t have that expertise or experience ," Mrs Haslam said .
" They ' re really quite uncomfortable about prescribing cannabis so we want to make them feel comfortable .
Who can get medicinal marijuana ?
The Federal Government has approved the sale of medicinal marijuana . But it still won ' t be easy for people to get a prescription .
" It ' s really important that we get international expertise here and guide our doctors ."
Mrs Haslam started campaigning for better access to medicinal cannabis after watching her son , Dan , die from bowel cancer two years ago .
" No medication that was given to him touched his nausea and vomiting until he touched cannabis ," she said . " It was that miraculous my husband and I looked at each other and said , ' My God , if this can do this for Dan then this is something that ' s worth fighting for '."
Mr Stoopman said the doctors ' training program and three-day symposium would be one of the most important events to understand and advance the uses of medical cannabis in Australia .
" I think Lucy Haslam has done a great job bringing international speakers and doctors together for this symposium ," he said .
Mrs Haslam said she hoped the symposium would lead to more patients having access to medical cannabis .