This study investigates the contents of prescription inquiries to improve the safety and quality of future medical care. We investigated the number and contents of inquiries regarding external prescriptions filed at the Tanabe Pharmacy Sojiji-mae store in 2010 and 2012 issued by Tsurumi University Dental Hospital. The questions were mainly about safety, including the (1) dosage/administration of a drug, (2) prescription of a drug to which a patient has a history of allergy/adverse reaction, (3) prescription of a drug of the same type or with the same effect as a drug that a patient is currently taking, and (4) prescription of a drug that is contraindicated for or instructed to be carefully used in combination with a drug that a patient is currently taking. Most of the prescription inquiries could be avoided if the issuing physician had the basic knowledge of relevant drugs and maintained an accurate record patients’ history of medication. Educating physicians on these points is likely to improve the safety and quality of medical care.