alum
Meaning of alum: Alum is an astringent mineral salt used to stop minor bleeding, treat minor skin irritation, and boost vaccine effectiveness.
Definition of alum
Alum is a chemical compound generally consisting of aluminum sulfate combined with a second sulfate salt, most commonly potassium sulfate. It has astringent properties, meaning it causes tissue and small blood vessels to constrict, an effect that has made it useful for stopping minor bleeding from small cuts and skin irritation.
Alum has been used for centuries, including historically in water purification and in tanning and dyeing processes, alongside its longstanding use as a styptic to control minor bleeding.
In modern medicine, aluminum based compounds related to alum are used as an adjuvant in certain vaccines, meaning they are added to boost the immune system's response to the vaccine's active ingredient, a distinct use from alum's traditional astringent applications.
Used in a sentence
A styptic pencil containing alum was used to stop minor bleeding from a small shaving cut.
Good to know
Alum's role as a vaccine adjuvant, boosting immune response, is a distinct use from its traditional astringent application for minor bleeding, and the two uses rely on different properties of the compound.
Word origin
Where “alum” comes from
Formed from Latin alumen, an astringent mineral salt known and used since antiquity.