CBD oil may potentially interact in a negative way with anti-epilepsy drugs. As of now, only in vitro (test tube) observations exist with no living organism testing proving safety. Drugs that may interact include:
Links
[1] https://www.thehealthyhomeeconomist.com/cbd-oil-dangers/
[2] http://www.rethinkpot.org/tags/hash-oil
[3] http://www.rethinkpot.org/tags/cbd-oil
[4] http://www.rethinkpot.org/tags/pregnancy