Men have always sought the elusive unicorn, for the single
twisted horn which projected from its forehead was thought to
be a powerful talisman. It was said that the unicorn had
simply to dip the tip of its horn in a muddy pool for the water
to become pure. Men also believed that to drink from this horn
was a protection against all sickness, and that if the horn was
ground to a powder it would act as an antidote to all poisons.
Less than 200 years ago in France, the horn of a unicorn was
used in a ceremony to test the royal food for poison.

Although only the size of a small horse, the unicorn is a very
fierce beast, capable of killing an elephant with a single
thrust from its horn. Its fleetness of foot also makes this
solitary creature difficult to capture. However, it can be
tamed and captured by a maiden. Made gentle by the sight of a
virgin, the unicorn can be lured to lay its head in her lap, and
in this docile mood, the maiden may secure it with a golden rope.
[ Mythical Beasts, by Deirdre Headon (The Leprechaun Library) ]

Martin took a small sip of beer. "Almost ready," he said.
"You hold your beer awfully well."
Tlingel laughed. "A unicorn's horn is a detoxicant. Its
possession is a universal remedy. I wait until I reach the
warm glow stage, then I use my horn to burn off any excess and
keep me right there."
[ Unicorn Variations, by Roger Zelazny ]