Potassium alum is used in medicine mainly as an astringent (or styptic) and antiseptic.

Styptic pencils are rods composed of potassium alum or aluminum sulfate, used topically to reduce bleeding in minor cuts (especially from shaving) and abrasions, nosebleeds, and hemorrhoids, and to relieve pain from stings and bites.
 Potassium alum blocks were rubbed over the wet skin after shaving.

Potassium alum was also used topically to remove pimples and acne, and to cauterize aphthous ulcers in the mouth and canker sores, as it has a significant drying effect to the area and reduces the irritation felt at the site.
It has been used to stop bleeding in cases of hemorrhagic cystitis.
and is used in some countries as a cure for hyperhidrosis.

It is used in dentistry (especially in gingival retraction cords) because of its astringent and hemostatic properties.

Potassium and ammonium alum are the active ingredients in some antiperspirants and deodorants, acting by inhibiting the growth of the bacteria responsible for body odor.
 Alum's antiperspirant and antibacterial properties contribute to its traditional use as an underarm deodorant.
It has been used for this purpose in Europe, Mexico, Thailand (where it is called sarn-som), throughout Asia and in the Philippines (where it is called tawas).
Today, potassium or ammonium alum is sold commercially for this purpose as a "deodorant crystal".
 Beginning in 2005 the US Food and Drug Administration no longer recognized it as a wetness reducer, however it is still available and used in several other countries, primarily in Asia.

Potassium alum was the major adjuvant used to increase the efficacy of vaccines, and has been used since the 1920s.
But it has been almost completely replaced by aluminium hydroxide and aluminium phosphate in commercial vaccines.

Alum may be used in depilatory waxes used for the removal of body hair or applied to freshly waxed skin as a soothing agent.

In the 1950s, men sporting crewcut or flattop hairstyles sometimes applied alum to their hair, as an alternative to pomade, to keep the hair standing up.
Potassium alum is used in medicine mainly as an astringent (or styptic) and antiseptic. 
Styptic pencils are rods composed of potassium alum or aluminum sulfate, used topically to reduce bleeding in minor cuts (especially from shaving) and abrasions, nosebleeds, and hemorrhoids, and to relieve pain from stings and bites.  Potassium alum blocks were rubbed over the wet skin after shaving.
Potassium alum was also used topically to remove pimples and acne, and to cauterize aphthous ulcers in the mouth and canker sores, as it has a significant drying effect to the area and reduces the irritation felt at the site. It has been used to stop bleeding in cases of hemorrhagic cystitis. and is used in some countries as a cure for hyperhidrosis. 
It is used in dentistry (especially in gingival retraction cords) because of its astringent and hemostatic properties.
Potassium and ammonium alum are the active ingredients in some antiperspirants and deodorants, acting by inhibiting the growth of the bacteria responsible for body odor.  Alum's antiperspirant and antibacterial properties contribute to its traditional use as an underarm deodorant. It has been used for this purpose in Europe, Mexico, Thailand (where it is called sarn-som), throughout Asia and in the Philippines (where it is called tawas). Today, potassium or ammonium alum is sold commercially for this purpose as a "deodorant crystal".  Beginning in 2005 the US Food and Drug Administration no longer recognized it as a wetness reducer, however it is still available and used in several other countries, primarily in Asia.
Potassium alum was the major adjuvant used to increase the efficacy of vaccines, and has been used since the 1920s. But it has been almost completely replaced by aluminium hydroxide and aluminium phosphate in commercial vaccines.
Alum may be used in depilatory waxes used for the removal of body hair or applied to freshly waxed skin as a soothing agent.
In the 1950s, men sporting crewcut or flattop hairstyles sometimes applied alum to their hair, as an alternative to pomade, to keep the hair standing up.
Potassium alum