A medical prescription — the written document by a doctor authorizing medications to be dispensed at a pharmacy.
風邪で病院を受診し、処方箋をもらった。
I went to the doctor for a cold and received a prescription.
薬局に処方箋を出して薬を受け取った。
I handed the prescription to the pharmacy and received the medicine.
この薬は処方箋が必要なので、医師の診断を受けてください。
This medicine requires a prescription, so please see a doctor.