U.S. regulators warned a leading marijuana company for making unproven health claims about CBD, the trendy ingredient that's turning up in lotions, foods and pet treats.

The Food and Drug Administration announced Tuesday it warned Curaleaf Inc., of Wakefield, Massachusetts, for illegally selling unapproved products. Curaleaf's claims could lead people to delay medical care for serious conditions like cancer, the agency said.

"Consumers should beware of purchasing or using any such products," said Acting FDA Commissioner Ned Sharpless in a statement.

The FDA has issued similar warning letters to smaller businesses, but this is the first since the agency began studying how it regulates CBD. The agency plans to report in the fall on its regulatory approach after holding a public hearing and receiving nearly 4,500 comments.

The agency is exploring "potential regulatory pathways" for some CBD products to be lawfully marketed, Sharpless said.

Curaleaf, which operates in 12 states, said it will work with the FDA to resolve the issues mentioned in the warning letter. The company's shares fell more than 7% on the news, and some other cannabis stocks lost ground.

"The company is fully committed to complying with FDA requirements for all of the products that it markets," Curaleaf said in a statement.

CVS Health, which started carrying CBD skin products in some states this year, plans to remove Curaleaf from its shelves following the FDA's warning, said CVS spokesman Mike DeAngelis in an email. The drugstore chain has been selling Curaleaf CBD lotion and skin patches. CVS does not sell any CBD supplements or foods, DeAngelis said.

CBD is a compound found in marijuana that doesn't cause a high. Its skyrocketing popularity has attracted mainstream retailers despite little evidence of its health claims.

Curaleaf's website and social media accounts show the company is illegally selling unapproved new drugs, the FDA said, specifically its CBD lotion, a pain-relief patch, several tinctures and disposable vape pens.

The company's Bido CBD for Pets products are unapproved new animal drugs, the FDA said.

The FDA cited claims the company made for CBD's effectiveness in treating chronic pain, anxiety, attention deficit disorder, Alzheimer's disease, Parkinson's disease, cancer and opioid withdrawal.

Curaleaf said all its CBD products come from hemp, a version of the cannabis plant that is low in THC, the part of cannabis that gives pot its high.

Hemp gained new status as an agricultural crop late last year when President Donald Trump signed the farm bill.

The CBD industry hoped the legislation would allow broad sales of the ingredient.

But the FDA still regulates pharmaceutical products. Since CBD is the active ingredient of GW Pharmaceuticals' Epidiolex, approved by the FDA last year, the agency has said it can't be added to food or marketed to treat health conditions without going through the FDA's established processes.