The makers of Nabisco’s Chewy Chips Ahoy! are recalling boxes of the treats over a mysterious “solidified ingredient” that could sicken customers, according to officials.

“Some reports of potential adverse health effects have been received,” the cookie firm Mondelez Global LLC said in a press release.

The voluntary recall is limited to 13-ounce packages with “best sell by” dates of Sept. 7, 8, 14 and 15 of 2019 in the US, according to the firm.

Anyone with problem packages is urged to toss them in the trash or return them to stores for a full refund.

Customers can contact the company at 1-844-366-1171 for more information.