Dollar Shave Club is hitting back against Proctor & Gamble Co.’s allegations of patent infringement by counterclaiming that the razor behemoth’s patent is invalid.

Proctor & Gamble Co. sued subscription razor business Dollar Shave Club in December for alleged patent infringement, claiming that a razor coating patent was violated. The company is seeking an injunction against Dollar Shave Club’s razor.

Dollar Shave Club of Venice is an online razor subscription service that has grown rapidly since its founding in 2012, thanks in large part to a funny commercial featuring founder and Chief Executive Michael Dubin that went viral on the Internet.

Dollar Shave Club’s counterclaim, filed Tuesday, was dismissive of Proctor & Gamble’s lawsuit.

“Dollar Shave Club does not infringe on any valid and enforceable claim of the Gillette patent,” Dollar Shave Club added in a statement. “We will vigorously defend ourselves and our three million members against these meritless claims.”

Dollar Shave Club reported revenue of $64 million in 2014, up from $19 million the year earlier, and said sales were $153 million last year.

In contrast, sales of Proctor & Gamble’s higher-priced razors, such as Gillette, have been hurt by Dollar Shave Club’s growth, as well as the increased popularity of facial hair, in recent years. The company has responded to Dollar Shave Club’s subscription model by launching its own higher-priced rival, Gillette Shave Club, in June.

Technology reporter Garrett Reim can be reached at [email protected]. Follow him on Twitter @garrettreim for the latest in L.A. tech news.