Andrographis is the king of bitters–that is bitter herbs which have blood cleansing properties. If you have sinus problems, bronchitis, a cold, you will want to take andrographis as it helps thin the congestion enabling you to expel it. Several studies during cold and flu season have shown that taking this herb may prevent the onset of an illness. Andrographis is a small annual plant growing primarily in Southern tropical Asia. All parts of the plant, leaf, stem and root, are bitter; but it is primarily the leaf that is used herbally.