Kellogg's popular Rice Krispies cereal had a crisis in 2010 when it was accused of misleading consumers about its immunity boosting properties. The Federal Trade Commission ordered Kellogg to halt all advertising that claimed that the cereal improved a child's immunity with "25 percent Daily Value of Antioxidants and Nutrients -- Vitamins A, B, C and E," stating the the claims were "dubious."
Just a year prior, the company settled with the FTC over charges that its Frosted Mini-Wheats cereal didn't live up to its ads. The campaign claimed that the cereal improved kids' attentiveness by nearly 20%, and was shot down when the FTC found out that the clinical studies showed that only 1-in-9 kids had that kind of improvement -- and half the kids weren't affected at all.