CBD: Safe and effective?

Answer Section

By Mayo Clinic Staff

A prescription cannabidiol (CBD) oil works as an effective treatment for certain rare seizure conditions. But further research is needed to determine whether CBD has other benefits and how safe it is to use.

CBD is a chemical found in marijuana. CBD in its pure form doesn't contain tetrahydrocannabinol (THC), the part of marijuana that causes a "high." But many CBD products sold to the public contain small amounts of THC. In some products, the amount is higher than what the label shows.

Currently, the only CBD product approved by the U.S. Food and Drug Administration (FDA) is a prescription liquid called Epidiolex. It's approved to treat seizures caused by Lennox-Gastaut syndrome, Dravet syndrome and tuberous sclerosis complex.

Laws about CBD use vary by state and country. CBD is still being studied as a treatment for a wide range of conditions, including Parkinson's disease, schizophrenia, diabetes, multiple sclerosis and anxiety. But there isn't much proof that CBD works for these uses.

CBD is most often sold as an oil, but CBD also is sold as extracts, vape liquids and capsules. Many foods, drinks and beauty products sold online claim to contain CBD. However, in the U.S., it's not legal to add CBD to foods or dietary supplements. These products have not gone through rigorous testing for safety, quality or accurate labeling.

CBD use also carries some risks. Some people tolerate CBD well, but others have side effects. These may include rash, diarrhea, vomiting, loss of appetite, infection, liver injury, drowsiness and tiredness. CBD also can interact with other medicines and raise the risk of side effects. These medicines include blood thinners, antiseizure drugs and sedatives.

The FDA strongly advises against using CBD during pregnancy or while breastfeeding. There may be risks to the unborn baby, also called a fetus. And there's not enough information about how CBD affects pregnancy or breastfeeding.

Another concern is that CBD products may not contain what the label shows. In one study of 84 CBD products bought online, more than a quarter of the products contained less CBD than the amount on the label. Also, THC was found in 18 of the products.

If you're thinking about using CBD products, talk with your healthcare professional first.