What is the best medicine to get mucus out of your lungs?

Excuse me, could you please elaborate on what would be considered the optimal medication for clearing mucus from the lungs? Is there a specific type of medication that has proven to be more effective than others in achieving this goal? Additionally, are there any potential side effects or precautions one should be aware of when taking such medication? It would be greatly appreciated if you could provide some insight into this matter.