Most people consider over-the-counter medications to be "safe" but that can be the far from an accurate deduction. It is wise to always when you are purchasing any medication, be it prescription or over-the-counter to consult with the pharmacy staff to see if there are any interaction with other medications you may be taking, supplements, herbs or foods. My family found this out the hard way when my father began taking ginko (a common herbal product that people takes for memory enhancement) and also was on a blood thinner for a heart condition. We could not figure out for months why he was experiencing nose bleeds which required numerous emergency room visits and eventually the need for a tranfusion. Finally a physician during one of his ER visits asked if he was taking any herbal supplement and bingo...we found that ginko was the problem...you cannot mix the two. Had we asked the pharmacist before purchasing the ginko, they would have pulled up my fathers medication profile and seen that interaction. This is just one of the many interaction that can occur between medications, supplements and food...some being very serious and life threatening.
Remember that section at the pharmacy counter that says "consultation" it is there to help keep you and your loved ones safe...us it.