The FDA hit two online marketers with warning letters for selling unapproved, misbranded products containing kratom.

The two companies — Cali Botanicals of Folsom, California and Kratom NC of Wilmington, North Carolina — claimed on their websites and through social media that their products could treat opioid addiction, withdrawal symptoms, depression, anxiety and cancer. The claims were not cleared by the FDA.

“These products have not been demonstrated to be safe or effective for any use and may keep some patients from seeking appropriate, FDA-approved therapies,” the agency said.

“As we work to combat the opioid crisis, we cannot allow unscrupulous vendors to take advantage of consumers by selling products with unsubstantiated claims that they can treat opioid addiction or alleviate other medical conditions,” said acting FDA Commissioner Ned Sharpless.