Strep throat? How do you know you have a strep throat? If you have had a positive test, your doctor should have prescribed antibiotics. This also goes for urgent care centers, where physician's assistants and nurse practitioners can prescribe antibiotics. Otherwise, you only have mouthwash (listerine) and lozenges. Salt water gargles may help soothe--use 1 tablespoon salt per quart of water. But really, see md!