There is a difference between what is considered "safe" and what is considered therapeutic. According to an article in the New England Journal of Medicine, "marijuana, in its natural form, is one of the safest therapeutically active substances known to man…. At present it is estimated that marijuana’s LD-50 [median lethal dose] is around 1:20,000 or 1:40,000. In layman’s terms… a smoker would theoretically have to consume 20,000 to 40,000 times as much marijuana as is contained in one marijuana cigarette… nearly 1500 pounds of marijuana within about fifteen minutes to induce a lethal response."
Essential, it is "safe" to intake high doses of cannabis and its cannabinoids such as THC and CBD. An excessive amount of CBD could be less effective therapeutically than a moderate dose. “Less is more” is often the case with respect to cannabis therapy. But, how much is necessary for a therapeutic dose? It varies depending on the disease and/or symptoms and can range anywhere from 2.5mg – 1,280 mg CBD daily, that is why it is important for you seek a medical marijuana provider to properly guide you.