Kim and Khloe Kardashian may have gotten themselves into legal hot water with their promotion of the diet drug QuickTrim.

According to the New York Post, the New York City law firm Bursor & Fisher has filed a class-action against QuickTrim's manufacturers, Windmill Health Products in New Jersey, for the product's promotion and marketing claims, which include the Kardashian sisters as celebrity users of QuickTrim.

In an email sent to Quick Trim customers, the Post reported, the company  noted, "The active ingredient in QuickTrim weight loss products is a large dose of caffeine. …  The FDA has determined that caffeine is not safe or effective for weight loss."

QuickTrim was hitched to Kim and Khloe's star in 2009 when the duo  became the product's celebrity endorsers. In January 2010, Kim claimed that she used QuickTrim and dropped 15 pounds. Khloe professed a similar weight loss a few months later. Since then, the product has earned Windmill Health Products $45 million in revenue.

The products are sold nationwide at such chains as Walmart, CVS  and Walgreens. The company's website claims that QuickTrim products, which range from pills to powdery drinks, can help burn calories, cleanse the bodies, curb appetite and boost energy. The website also says  that "These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."