Recently there has been some reports that people taking sleep aids containing aspirin (acetylsalicylic acid) have had problems with their livers. The problem is that aspirin may be contained in many products and as a result of taking several products one could have a larger than desired dosage of apspirin. I would like to call your attention to the fact that PowerSleep does not contain aspirin. see http://www.energywave.com/products/powersleep/powersleep.htm