Oak Bark is an astringent and tonic. It is _used externally_ in the form of decoction, to restrain bleeding from lacerated surfaces. As a local astringent, it is used in the form of decoction, as a gargle in sore throat and relaxed uvula. It is _used internally_ in the same diseases as catechu, and when combined with aromatics and bitters, in intermittent fevers. _Dose_ of the _powder_, from fifteen to thirty grains; of the _decoction_, from two to eight drachms.