A lawsuit in federal court in Massachusetts alleges that Hasselbeck lifted "word for word" content from a book on celiac disease written by a self-published author on Cape Cod.
Hasselbeck's book, "The G-Free Diet: A Gluten-Free Survival Guide" has appeared over the last month in several best-selling lists.
The lawsuit was filed by author Susan Hassett, who says she sent Hasselbeck a copy of her "Living With Celiac Disease" book as a courtesy after the TV celebrity disclosed she had the illness last year.
A lawyer for Hassett declined to comment Tuesday. A phone message left with Hasselbeck's agent, Andy Cohen, was not immediately returned.