Today, the Federal Trade Commission made a rare move to start legal action against a detox tea company for making unsubstantiated health claims and paying influencers like rapper Cardi B and singer Jordin Sparks to post Instagram ads without disclosing that they were paid.

According to the FTC complaint, the Teami website claimed its teas could fight cancer, unclog arteries, stop migraines, and treat colds. It also claimed its diet products could burn fat, boost metabolic rate, and cause substantial weight loss.

Teami sells teas under names like Teami Colon and Teami Skinny, as well as skincare products like Teami Detox Mask.

Representatives for Cardi B and Sparks, who were paid an undisclosed amount of money for the ads, did not reply to request for comment by publication time.

The FTC has guidelines about the disclosures influencers must make in Instagram ads, but it’s rare for the FTC to actually file any lawsuits or take action, though undisclosed ads are rampant across the platform. To date, the FTC has only filed legal action against brands or advertising agencies, never the influencers promoting their products.

But this is the first time that the FTC has taken legal action against a company using influencer advertising to make unsubstantiated health claims.

“Today, there are more than 1 million Instagram posts that bear hashtags associated with detox teas on Instagram,” said Laura Smith, legal director of Truth in Advertising, a consumer advocacy group that has complained to the FTC about influencer ads on Instagram in the past. “This means that on any given day, a countless number of young consumers are exposed to this egregious and widespread deceptive marketing issue.”

In this case, 10 influencers — Cardi B, Jordin Sparks, TV host Adrienne Bailon, actor Alexa PenaVega from Spy Kids, model Brittany Renner, Darnell Nicole from WAGS Miami, actor Jenicka Lopez, actor Leyla Milani, Instagrammer Princess Mae Love, and fitness influencer Katya Elise Henry — received sternly worded warning letters saying that they needed to tell the FTC how they plan to properly disclose such ads in the future. Other paid Teami influencers, like Kylie Jenner and Demi Lovato, who in the past have promoted the company’s tea, did not receive letters.

Andrew Smith, director of consumer protection at the FTC, said on Friday that the influencers didn’t disclose their ads until the viewer clicked “more” on the caption.

“That’s not good enough,” Smith said.

The FTC’s action took place simultaneously with Teami, a Florida-based company, agreeing to a settlement of $1 million, which will go back to customers, though it will take some time to identify them. In addition to the financial penalty, Teami has agreed to do clinical testing on humans to prove its health claims.