>> we can test for pesticides, we can test for molds, mildews, we can test for residual solvents. >> testing for contamination. one of the biggest hurdles to creating a safe product. recent studies on the contamination on medical marijuana are pretty alarming. one paper showed pesticide residue as high as 69% in a batch of medical marijuana. it's one of the things that concerns main stream doctors about medical marijuana, safety, as well as uniformity and reliability. >> the major issue that physicians have is in the consistency of the product. how do you know what the person is getting? and the answer is, we don't. >> neurologist dr. edward mau is the chief of denver's epilepsy program. he's one of several main stream doctors now researching the stanley's marijuana after hearing about its dramatic results. >> my ears perked up. maybe this is something we should be investigating.