The word is Alexipharmic and it is defined as, an antidote against poison. A synonym is alexiterical, and the Greeks used both words to mean protective amulets. The last bit of information is from Onelook.

And here is the story that led me to Alexipharmic. I was reading about Celadon this past weekend and came upon this nugget. Around the fifteenth/ sixteenth centuries, Celadon became highly prized in Central Asia and Europe and hundreds of pieces were collected by the kings of the region. The popular belief at the time, was that celadon bowls had an alexipharmic quality and so were able to vitiate the effects of possible food poisoning by enemies of the King. The Ottomans collected a large quantity of Celadon pottery and the collection is housed to this day in the Topkapi palace in Istanbul.

Celadon was invented as a glaze by the Tang dynasty in eight century China and was an extremely rare and valuable example of Chinese pottery both in the region and beyond. The term is now also used to describe the pottery itself.

Here's a link to the Met, with a picture of a Korean bottle with just such a glaze.
http://www.metmuseum.org/toah/ho/07/eak/hod_27.119.6.htm

A word I never saw before. The alexi- part could be used in some interesting coinages. I couldn't access the site, got an error message.
The Celadon part is also interesting. Allegedly related
to character in Ovid's Metamorphoses.
cel[a[don 7sel4! d9n#, 3d!n8
n.
5Fr c=ladon, a delicate green, earlier, a tender lover, after C=ladon, the hero in Astr=e, romance by d‘Urfe (1610) < L (< Gr Keladbn), character in Ovid‘s Metamorphoses6 a pale grayish green
cel[a[don 7sel4! d9n#, 3d!n8
n.
5Fr c=ladon, a delicate green, earlier, a tender lover, after C=ladon, the hero in Astr=e, romance by d‘Urfe (1610) < L (< Gr Keladbn), character in Ovid‘s Metamorphoses6 a pale grayish green
cel[a[don 7sel4! d9n#, 3d!n8
n.
5Fr c=ladon, a delicate green, earlier, a tender lover, after C=ladon, the hero in Astr=e, romance by d‘Urfe (1610) < L (< Gr Keladbn), character in Ovid‘s Metamorphoses6 a pale grayish green
celadon
n.
5Fr c=ladon, a delicate green, earlier, a tender lover, after C=ladon, the hero in Astr=e, romance by d‘Urfe (1610) < L (< Gr Keladbn), character in Ovid‘s Metamorphoses6 a pale grayish green

For wwh, and everyone else who tried,
Sorry about the link; I just tried it and it's a dud all right. I don't know why it isn't connecting, but here's another that takes you straight to the collection in the Topkapi Palace.

http://www.ee.bilkent.edu.tr/~history/porcelain.html