CBD has been found to be highly effective in managing migraines, pain and inflammation, and is neuroprotective. It has been used, with anecdotal success, as a preventive medicine for seizure disorders. When considering CBD oil, be sure to look for oils extracted with CO2. In the past, butane has been used; and some manufacturers continue to use this potentially toxic substance.
CBD oils contain CBD extracted from either cannabis or hemp, which share the same genetics. It follows that all CBD oils should have the same medicinal properties. However, the concentration of CBD in any particular product may vary. In most patients, one to two drops/sprays applied under the tongue for ten seconds helps reverse or blunt the migraine when treated as early as possible.
As long as the CBD/THC ratio is greater than or equal to 1/1, you should not experience any psychoactive effects from THC. I usually recommend starting with a 4/1 ratio of CBD/THC and either increase or decrease the ratio depending on effectiveness and any adverse effects. CBD may cause some sedation/sleepiness.
Remember that it may take at least 30 minutes to begin to feel the effects; so it is better to wait a couple hours before increasing your dose. Every patient has a different metabolism and tolerance, so it may take some time to find the best dose for you.
Some patients that have really frequent migraines have found that a low dose CBD-containing edible taken after breakfast reduces their migraine frequency.