The Yelp app logo is displayed on an Apple iPad in Des Plaines, Illinois, U.S., on Tuesday, Feb. 5, 2013. Photographer: Tim Boyle/Bloomberg

If you've ever left a negative review of a company online, you might be pleased to hear that federal regulators have your back.

In a lawsuit announced Monday, the Federal Trade Commission accused a Florida-based firm not only of selling weight-loss supplements that didn't work as advertised, but also of improperly going after customers who complained about the faulty products online.

The company in question, Roca Labs, said that its nutritional powder could help users lose so much weight that it could be considered an alternative to gastric bypass surgery, according to the federal complaint. It also allegedly claimed that users could lose 21 pounds in as little as a month, and that it would work substantially on 90 percent of people.

But what positive recommendations you might find out there may have been paid for by Roca Labs itself. The company offered to cover half the price of its product in exchange for a glowing testimonial, according to the FTC.

Internet forums filled with negative feedback seem to paint a different picture of the company than the one Roca Labs was paying for. One consumer claimed she started feeling ill after taking the powder. Another called it a "lie" and that it landed the user in the hospital.

Unbeknownst to many, according to the FTC, Roca Labs had a "gag clause" in its fine print that allowed it to sue, and threaten to sue, people who criticized the company. Roca Labs allegedly included a copy of these terms in every shipment to consumers, and punished "violators" by making them pay hundreds of dollars.

The tactic ultimately made it harder for consumers to determine if they should buy the product, the FTC says, and the suppression of criticism almost undoubtedly propped up Roca Lab's sales. Should the FTC win its suit, it'd be a blow to the use of gag clauses by companies that fear the consequences of open criticism.

The FTC suit is the latest move amid a wider government crackdown. Earlier this month, a number of senators introduced legislation that would ban their usage in company legalese. It joins a companion bill in the House that was introduced in April.