I started taking this after contracting pneumonia from an overseas trip.
This really gave relief when all my lozenges, cough syrups had little effect on me. Took this for a total of 1 month, and I think even if you are not sick, this will really help your immune system fight sickness better.
Note that it does affect the taste of your beverages, that's why I mix this with the super-five mushroom or just plain warm water instead. I also had my husband take this for his coughs and it also helped him recover faster than usual.