Some medicines may interfere with the effects of your chemotherapy. To ensure that your treatment is the most effective that it can be Tell your doctor or nurse about any and all prescription and nonprescription medicines you are taking. Make a list of the name of each drug, who prescribed it, how often you take it, the reason you take it, and the dosage. Be sure to include some of the preparations you may not think of as medicines. These would be aspirin, herbal and dietary supplements, vitamins, and over-the-counter medicines. Your doctor will tell you if you should stop taking any of these medicines before you start chemotherapy. After your treatments begin, check with your doctor before taking any new medicines, or supplements and before stopping the ones you already take.