Mass. Gen. Laws ch. 111 § 25I
The commissioner shall promulgate regulations requiring that either a resident or consultant pharmacist in a health care facility shall return all unused medication to the pharmacy from which it was purchased provided that such medication is sealed in unopened, individually-packaged units and within the recommended period of shelf life and provided that such medication is not a schedule I or II controlled substance as defined in chapter 94C. Medication returned pursuant to this section shall be accepted by such pharmacies regardless of whether such medications are included on any list of unit-dose drugs issued by the department or by the division of medical assistance. The rules and regulations promulgated by the commissioner shall permit the pharmacy to which such medication is returned to restock and redistribute that medication. The pharmacy shall be required to reimburse or credit the purchaser for any such returned medication.
Mass. Gen. Laws ch. 111, § 25I