With so many people taking prescription medication, there is a distinct possibility that the side effects of such medications may be responsible for the symptoms for which patients seek chiropractic care. In a recent study in Australia, 549 prescription medications were used by 330 patients. A total of 104 individual medications were identified of which 69 listed headache as a potential side effect of their use. Fifty-seven patients who sought care for the treatment of headache were using medication which may produce headache as a side effect of its use. There is a need for chiropractors to be aware of the side effects of prescribed medication their patients may be taking. This is the case not only because of the potential for adverse interaction between treatments, but because symptoms produced by prescribed medication may be responsible for the patient’s clinical presentation.