There are currently no controlled trials to indicate that cannabis is effective in the treatment of cannabis; however, there are animal studies and anecdotal evidence that cannabis may prevent seizures. There are also studies that suggest cannabis is pro-convulsant.
CBD, cannabidiol, is the cannabinoid touted as being beneficial in seizure patients. Charlotte's web was developed by Colorado growers for an epileptic girl, has a high CBD content, and has the lowest THC content of which I am aware (<0.3% THC). Charlotte is a girl with Dravet syndrome who began treatment with Charlotte's web at the age of 5. Her parents and physicians say that cannabis treatment decreased her epileptic seizures.
If CBD is truly beneficial as an anti-epileptic medication, any product containing a high CBD content, such as the strain AC/DC, CBD concentrates, and CBD oils could theoretically help control seizures. More research is necessary to determine if this is the case, and there is no "best" treatment that has been elucidated. Any treatment should be undergone under the supervision of a neurologist.
How old is your daughter? We do have some restrictions regarding age so she must be considered an adult for us to do a recommendation for your daughter. You may watch the videos, "Weed, Weed 2 and Weed 3" available on YouTube for your viewing and these are 3 CNN Documentaries on the use of CBD cannabis for seizures but so far as far as I know there are no clinical trials that have been completedBecause our government has for business the use of cannabis for clinical trials with some exceptions. CBD cannabis works well for mood swings and depression and the CBDs are not psychoactive. If your daughter is under age you may have to take her to a local physician who recommends the use of CBD Cannabis for seizures but if she is on anti-seizure medication and do not stop the medication especially if it's working. She should be under a physician care in order to stop seizure medication. You may also want to look into free glutamate's, neurotoxic substances that may be in foods and not labeled. Consider eliminating all free glutamate's from your diet since they are neurologically toxic especially to people who have migraines or anxiety issues. Consider visiting www.truthinlabeling.org for more information.
Since it is hard to find Charlotte's Web strain here in California, I would suggest looking into the high CBD strain called AC/DC. We do produce a high CBD tinctures and have a few members with seizure disorders that are having good results with it, while also taking anti-seizure meds.