(Adds statement by Bayer)

WASHINGTON, Sept 12 (Reuters) - The American unit of Bayer AG is making unsubstantiated claims about its Phillips Colon Health product, the United States said on Friday as it sought to hold Bayer Corp in contempt of a court order for the statements.

Bayer claimed the product can "defend against" occasional constipation, diarrhea and other problems, but did not have reliable scientific evidence to support the description, the U.S. Department of Justice said.

The statement violates a 2007 court order that prohibited Bayer from making unsubstantiated claims about any dietary supplements it promotes or sells, the government said.

In a statement, the company said it was "extremely disappointed" in the government's decision and strongly disagreed with it.

"Phillips Colon Health is a safe and beneficial probiotic product. Bayer believes that the product's benefits for consumers are fully substantiated and supported," the company said.

(Reporting by Aruna Viswanatha in Washington and Jonathan Stempel in New York; editing by Leslie Adler and Matthew Lewis)