marijuana is made up of two ingredients, thc -- that's the psychoactive part that makes you high, and cbd, also called cannibadiol. they think it regulates electivity to help quiet the activity in the brain that causes seizures. >> dr. julie holland is the editor of the pot book, a complete guide to cannabis. >> for a long time the work on cannabis and epilepsy was sort of inconclusive. maybe it works. maybe it doesn't. they couldn't quite figure it out. it's only when they really started separating thc from cbd that they saw definitively, yes, cbd seems to really stop seizures. >> so the figgeys needed to find something that was rare, a strain of marijuana that was rare in thc. of course, they didn't want charlotte getting stoned. but also high in cbd to treat her seizures. and that wouldn't be easy. dispensaries and growers, they