Absolutely. Stomachaches are a very common side effects of ADHD medications (like Ritalin LA, Concerta, Focalin, Metadate, Dexedrine, and Adderall), which all rely on psychostimulant medications as the main ingredient. Sometimes taking the medication with food can help minimize the queasiness, since the worst of it tends to occur within the first hour or two. For most kids the belly aches usually begin to subside after several weeks on the drugs. If your child’s problems don't improve by then, talk to his doctor. He may be able to suggest a lower dose or a different drug that will be easier on his tummy.