Bausch Health has sued Sandoz for patent infringement over its irritable bowel syndrome drug Xifaxan (rifaximin).

The lawsuit in the U.S. District Court for New Jersey alleges that Sandoz’s ANDA for generic Xifaxan violates 14 out of 22 patents that Bausch and its subsidiaries Salix Pharmaceuticals and Alfagisma hold for the drug.

Sandoz sent a letter to Bausch and its subsidiaries advising that it had filed an ANDA for generic Xifaxan. Sandoz also advised that the submission included certifications that the company believed certain patents are “invalid, unenforceable and/or not infringed.”

Bausch wants the court to rule that the patents are valid and enforceable and that manufacturing a generic would infringe upon them. The company also asked the court to issue a permanent injunction against Sandoz’s generic until the patents expire and to set an FDA approval date for the ANDA that is after the patents expire.