Many health care providers practicing near the border between the United States and Mexico have serious concerns about their patients' using medications obtained in Mexico. Despite these concerns, the extent of this problem is not known. A survey administered in a publicly funded rural clinic and an urban private practice in southern New Mexico assessed this problem. The survey revealed that 87% of the rural clinic patients and 6% of the urban private practice patients had purchased medications in Mexico within the past two months. Further, 91% of the clinic patients and 56% of the private practice patients stated that they had, at some time, used medications from Mexico. Although many of these medications are fairly innocuous, their easy accessibility and lack of regulation can lead to serious health hazards.