<<Disclaimer: Verify this information before applying it to your situation.>> Hi, I just called Schering to verify Barbara's information and they advised me that Claritin uses corn starch as its inactive ingredient. They state that the supplier of the corn starch can change from batch to batch and they refuse to "guarantee gluten-free" for this reason. However, they also stated that they always use corn starch, no matter who the supplier is. This is good news! -Amy