Additionally, CBD may interact with existing medication. It is therefore important to discuss using CBD oil with your doctor beforehand, to help ensure it is used safely and any harmful effects are avoided.
Growing research is demonstrating how CBD oil can provide pain relief for people with certain health complications, without the addition of any mind-altering effects.
Cannabis pills containing only CBD and not THC were sold legally for the first time in Europe in 2015.
How to use CBD oil
A 2015 study of CBD oil effects in humans concluded that CBD is generally well-tolerated and considered safe. However, it can cause certain adverse reactions such as diarrhea and stomach ache. 
GW Pharmaceuticals, a UK-based company, has developed a cannabis spray called Sativex which utilises both CBD and THCV to help treat muscle spasms in multiple sclerosis. The company is in the process of developing a similar spray which could aid blood sugar control in type 2 diabetes.
By activating receptors such as adenosine, serotonin and vanilloid, CBD can affect your body temperature, inflammation and perception of pain.
CBD oil is believed to activate a number of receptors in the body, influencing the body to produce naturally-occurring cannabinoids.
Image: yavdat/Getty Images
CBD has been touted for a wide variety of health issues, but the strongest scientific evidence is for its effectiveness in treating some of the cruelest childhood epilepsy syndromes, such as Dravet syndrome and Lennox-Gastaut syndrome (LGS), which typically don’t respond to antiseizure medications. In numerous studies, CBD was able to reduce the number of seizures, and, in some cases, it was able to stop them altogether. Videos of the effects of CBD on these children and their seizures are readily available on the Internet for viewing, and they are quite striking. Recently the FDA approved the first ever cannabis-derived medicine for these conditions, Epidiolex, which contains CBD.
CBD stands for cannabidiol. It is the second most prevalent of the active ingredients of cannabis (marijuana). While CBD is an essential component of medical marijuana, it is derived directly from the hemp plant, which is a cousin of the marijuana plant. While CBD is a component of marijuana (one of hundreds), by itself it does not cause a "high." According to a report from the World Health Organization, "In humans, CBD exhibits no effects indicative of any abuse or dependence potential…. To date, there is no evidence of public health related problems associated with the use of pure CBD."
The bottom line on cannabidiol
Some CBD manufacturers have come under government scrutiny for wild, indefensible claims, such that CBD is a cure-all for cancer, which it is not. We need more research but CBD may be prove to be an option for managing anxiety, insomnia, and chronic pain. Without sufficient high-quality evidence in human studies we can’t pinpoint effective doses, and because CBD is currently is mostly available as an unregulated supplement, it’s difficult to know exactly what you are getting. If you decide to try CBD, talk with your doctor — if for no other reason than to make sure it won’t affect other medications you are taking.
CBD is commonly used to address anxiety, and for patients who suffer through the misery of insomnia, studies suggest that CBD may help with both falling asleep and staying asleep.
Side effects of CBD include nausea, fatigue and irritability. CBD can increase the level in your blood of the blood thinner coumadin, and it can raise levels of certain other medications in your blood by the exact same mechanism that grapefruit juice does. A significant safety concern with CBD is that it is primarily marketed and sold as a supplement, not a medication. Currently, the FDA does not regulate the safety and purity of dietary supplements. So, you cannot know for sure that the product you buy has active ingredients at the dose listed on the label. In addition, the product may contain other (unknown) elements. We also don’t know the most effective therapeutic dose of CBD for any particular medical condition.
CBD may offer an option for treating different types of chronic pain. A study from the European Journal of Pain showed, using an animal model, CBD applied on the skin could help lower pain and inflammation due to arthritis. Another study demonstrated the mechanism by which CBD inhibits inflammatory and neuropathic pain, two of the most difficult types of chronic pain to treat. More study in humans is needed in this area to substantiate the claims of CBD proponents about pain control.
CBD oil must be studied in randomized clinical trials on people, not animals, before it can be considered safe or effective for heart failure, Lundgren says. Until that happens, he advises against buying or using CBD. “There is some evidence that CBD can cause liver injury as well as lead to male infertility issues. When consumed with alcohol, individuals may experience increased drowsiness, which can lead to household injuries.”
Larry Allen, MD, MHS, University of Colorado Anschutz Medical Campus.
“Heart failure patients should know that while CBD has been touted as a wonder compound and seems to be in almost everything these days, it has never been shown to have any significant cardiovascular benefits in human studies,” says Scott Lundgren, DO, a transplant cardiologist at Nebraska Medicine in Omaha.
What We Know About CBD
When you use CBD oil, your liver breaks it down. During this process, it could interfere with your medications for heart failure or other heart conditions. “CBD has known interactions with warfarin, certain statins, calcium channel blockers, beta-blockers, and nitrates. Just because a supplement is ‘natural’ doesn’t mean that it is safe,” Lundgren says.
“Does it stimulate your appetite? Yes. Do people gain weight if they take it? Possibly true. Patients with severe heart failure do have cachexia,” or severe weight loss and muscle wasting, he says. “One could argue that people with nausea, lack of appetite, or who are losing weight could think CBD would help them. People with heart failure have a fair amount of discomfort, including edema [swelling] and somatic or pain-related issues, so you could think CBD has a role.”
Oxidative Medicine and Cellular Longevity: “Therapeutic Applications of Cannabinoids in Cardiomyopathy and Heart Failure.”
If you have heart failure, you might feel like you’re taking control of your own care by trying herbal treatments that don’t require a prescription. To be safe, talk to your cardiologist first: Ask questions about CBD oil and make decisions together about using this or any other supplement, Allen says.