WARNING: Do not use this product unless advised by a physician if you are pregnant, attempting to become pregnant or nursing; or if you are taking any medications or have any chronic disease, including hypertension (high blood pressure), diabetes, or an endocrine, auto-immune, depressive, bleeding or seizure disorder. Side effects may include headaches, dizziness, nausea or loss of appetite. Do not take melatonin while operating a motor vehicle or machinery. Do not drive or operate machinery within eight hours of taking this product or if you feel groggy. Not intended for individuals under the age of 18. Consult your physician if you are experiencing persistent sleep difficulties or for use beyond four weeks.