Cheerios' producer General Mills is having to recall millions 1.8m boxes of its cereal because of an "undeclared allergen" - wheat.
The company said Cheerios and Honey Nut Cheerios produced at its factory in Lodi, California, during two weeks in July were being recalled because "an isolated incident resulted in wheat flour being inadvertently introduced into the gluten free oat flour system"
"As a result, the products may contain an undeclared allergen – wheat – in products labelled as gluten-free," General Mills.
"Consumers with wheat allergies, celiac disease or gluten intolerance should not consume products bearing the affected code dates and should contact General Mills for a replacement or full refund," it added.
No other General Mills cereals are affected.