The Federal Trade Commission threatened Tuesday to take legal action against three CBD companies that have illegally advertised that their products can cure a panoply of ailments.

CBD, or cannabidiol, is one of hundreds of compounds found in the cannabis plant. Though it doesn’t have an intoxicating effect, many people have claimed that they find CBD relaxing. However, there is scant evidence that CBD can be useful to treat anything other than some rare forms of epilepsy.

That hasn’t stopped unscrupulous businesses from making outrageous claims for CBD.

One company claimed that CBD “works like magic” to relieve “even the most agonizing pain” better than prescription painkillers. Counter to the facts, they also claimed it could treat cancer, Alzheimer’s disease, multiple sclerosis, fibromyalgia, cigarette addiction, and colitis. There is no scientific proof that CBD works for any of those afflictions.

“It is illegal to advertise that a product can prevent, treat, or cure human disease without competent and reliable scientific evidence to support such claims," according to the FTC.

CBD often is sold in oils, creams, capsules, tinctures, foods, and gummies.

An FTC spokesman said that any advertisement claiming magical properties for a product should be considered a “red flag.”

The FTC did not identify the companies by name. In the letters, the FTC warned that pitching CBD products without proof could violate the FTC Act and could result in legal action, injunctions, and an order to return money to consumers.

Industrial hemp -- from which most CBD is derived -- was legalized under the 2018 Farm Bill. The Food and Drug Administration has not approved its use in food products or in dietary supplements. CBD researchers are investigating whether CBD can be used to treat autism and anxiety, but they have not completed any substantial studies.

There is some evidence that CBD can interact with prescription medications, increasing or decreasing the effects of other drugs. Some patients give up their prescriptions, believing that CBD will provide an adequate solution to their ailments.