If you read the herbal literature from past centuries, epilepsy stands out as one of the most difficult conditions to treat. As with any long term condition, I would advise getting the most thorough diagnosis using modern technology from expert neurologists (doctors who study the workings of the brain). Always check the credentials of the doctor you are working with and talk to him about his training and the research he has been involved with.
You may think I am being over-cautious, but I've been involved with teenagers who were misdiagnosed as having epilepsy by a consultant paediatrician who decided he could become a paediatric neurologist with no training at all. He completely damaged the lives of more than 500 children by prescribing anti-epileptic medication for ten years and when their parents complained, upped their dosages!
As well as getting appropriate and useful tests and diagnosis, the next step is to learn as much as you can about how the brain works and what the different forms of epilepsy mean. Good quality, patient focused information can be found on the Equip website. Their epilepsy page ishttp://www.equip.nhs.uk/HealthTopics/epilepsy.aspx
I would also look at information concerning food stuffs and chemicals which can trigger epileptic conditions. There has been a lot of discussion about the new chemical sugar substitutes triggering epilepsy in susceptible individuals and, if it were me, I would be removing anything in my diet which had a label of "no-sugar" or low sugar. Learn to read the labels of any food you buy to ensure these sugar substitutes have not been added.
You asked about using herbs to manage epilepsy. This is not a condition I have any experience with and I would strongly suggest you seek a qualified medical herbalist living in your area who has experience and knowledge. If you live in the UK, go to the website of the National Institute of Medical Herbalists and use their 'find a herbalist' database to seek someone locally. Their website ishttp://www.nimh.nih.gov/index.shtml.
If you live outside the UK, let me know and I will ask the question for you on Henriette's Herblist.
I'm sorry that I have not answered your question. Yes, there are herbs which can support the body when suffering from epilepsy, but you need advice and hands on care from someone who really knows what they are doing. The herbs will also have to be taken within a total lifestyle management, not as a response to an event or as a general preventative. Allopathic medicines, well-diagnosed and managed can keep people well and fit free for the majority of their lives. (I used to have a member of staff who suffered with epilepsy and she was fine as long as she kept away from flickering flurescent lights!)
Good luck with your investigations