Salicylic acid and salicin (q.v.) share the properties common to the group of aromatic acids, which, as a group, are antiseptic without being toxic to man - a property practically unique; are unstable in the body; are antipyretic and analgesic; and diminish the excretion of urea by the kidneys.
When salicin is taken internally no irritant action occurs, nor is there any antisepsis.
It has now been established that, provided the kidneys be healthy, natural salicylic acid, sodium salicylate prepared from the natural acid, and salicin, are not cardiac depressants.
It is found in the volatile oils of Spiraea, and can be obtained by the oxidation of the glucoside salicin, (C13H1807), which is found in willow bark.
A valuable medicinal glucoside named salicin (q.v.) is also extracted from the bark.
The powdered bark is sometimes given to horses as a vermifuge; it possesses likewise tonic and febrifugal properties, containing a considerable amount of salicin.