Reye's syndrome: children and teenagers who have or are recovering from chicken pox or flu-like symptoms should not use this product. When using this product, if changes in behavior with nausea and vomiting occur, consult a doctor because these symptoms could be an early sign of reye's syndrome, a rare but serious illness. Allergy alert: aspirin may cause a severe allergic reaction, which may include: asthma (wheezing), hives, facial swelling, shock. Stomach bleeding warning: this product contains an nsaid, which may cause severe stomach bleeding. The chance is higher if you: are age 60 or older, have had stomach ulcers or bleeding problems, take a blood thinning (anticoagulant) or steroid drug, take other drugs containing prescription or nonprescription nsaids [aspirin, ibuprofen, naproxen, or others], take more or for a longer time than directed, have 3 or more alcoholic drinks every day while using this product. Do not use - if you are allergic to aspirin or any other pain reliever/fever reducer, if you have ever had an allergic reaction to this product or any of its ingredients.