Many breast cancer patients stop taking tamoxifen before completing their regular 5-year endocrine therapy. Approximately 22.1% of patients stop taking the drug within the first year of treatment and 35.2% within 3.5 years of treatment; this puts patients at a high risk of recurrence. These findings provide some clues as to why patients stop taking their medications, and perhaps older patients may have cognitive deficits that make them forget to take their medications. In addition, older patients and physicians may recognize that the absolute survival benefit of drug therapy decreases with shorter life expectancy, so the balance between the benefits and side effects of drugs becomes useless for older patients and those with coexisting disease with limited lives. Younger female breast cancer patients have difficulty accepting the menopause-like side effects caused by oral tamoxifen. Female breast cancer patients aged 35-40 years and >75 years were most likely to discontinue tamoxifen during treatment (hazard ratio 1.36 versus 1.46, respectively). Patients taking antidepressants prior to starting tamoxifen treatment were also most likely to discontinue the drug. The impact of non-adherence to medication has been recognized through a large study. One of the reasons why there has not been a full set of interventional studies on medication adherence, which is available today in the cancer field, is that patients change therapists or are not seeing them. Patients who frequently forget to take their medications can be reminded to take their medications using a medication log or a pill box that helps to record the dosage. Scheduling refills to coincide with other regular activities is another piece of advice she offers to patients. Medication side effects are another reason for not adhering to medication, and effective interventions are useful. Vitamin E or selective 5 serotonin reuptake inhibitor antidepressants can improve hot flush symptoms; skeletal muscle symptoms due to aromatase inhibitors can be treated with nonsteroidal antipyretic analgesics; and vaginal dryness symptoms can be improved using over-the-counter medications. But if the patient and physician wish to clarify these issues, they need to talk to each other. The patient needs to talk to the doctor about these issues, and the doctor should ask the patient about them. The best thing a doctor can do on an individual level is to consider the probability of not staying on the medication and ask the patient in a non-interrogative tone, such as how is it going? Did you remember to take your medication? Are you having problems taking your medication? The more communication you have, the better you can discern the issues of adherence and the need for intervention to help patients take their medications on time and in full.