NATICK, MASS. >> The parents of a 6-year-old Natick girl with peanut allergies have sued a restaurant because their daughter became extremely ill after eating a grilled cheese sandwich with peanut butter on it.

The suit filed in Middlesex Superior Court against Panera and a group of New England Panera franchises alleges negligence.

John Russo tells The Boston Globe his daughter required hospitalization after eating the sandwich ordered Jan. 28 via the online ordering system. He says his wife mentioned the peanut allergy twice on the order.

He says he was told by a store manager that the mistake was due to a "language" issue and the person who made the sandwich may have seen the word "peanut" and thought that was an instruction to add it.

A Panera spokesman refused comment.