Question: what is the best over the counter drug for bronchitis?
Answer: Drink lots of fluids, especially water. Try eight to 12 glasses a day to help thin out that mucus and make it easier to cough up. ... 
Get plenty of rest.
Use over-the-counter pain relievers with ibuprofen (Advil, Motrin), naproxen (Aleve), or aspirin to help with pain.