Welcome to the forum theyuw.
Look up the ingredients to check for possible allergies! I found what is claimed to be lists by searching clear lungs reviews online. Still, some ingredients were not specified.
Personally, I use guaifenesin extended release tablets, available OTC. Cheap, thins mucus so the cilia in the breathing tubes can clear it. I won't use anything with unknown ingredients. Reviews can be faked!
Ask your doctor before just using anything.