RELATED: Click here for the full list of recalled products
But North Chicago, Ill.-based Abbott says it recalled the 5 million cans of Similac powdered formula only as a precaution, and it's unlikely any product sold is contaminated.
Doctors also say chances for serious illness are slim in babies who drink formula containing bug parts.
Still, parents like Stephanie Roseman of Farmington Hills, Mich., are upset. She said on Thursday that her 3-month-old son seemed like he had a stomach ache this week. So Roseman is switching to a rival formula.
Abbott says it uncovered the insects last week at a manufacturing plant in Sturgis, Mich.
Abbott set up a consumer hotline, (800) 986-8850, which as of Thursday was overwhelmed with calls. Additional hotlines are expected.
Similac Recall Information: http://www.similac.com/recall