ARSENIC, n. A kind of cosmetic greatly affected by the ladies, whom it greatly affects in turn.
"Eat arsenic? Yes, all you get,"Consenting, he did speak up;"'Tis better you should eat it, pet,Than put it in my teacup."—Joel Huck
2009 Update: A metal element used in the past to cure communicable diseases such as syphilis and egalitarianism. Less toxic antibiotics have since been discovered as well as more lethal anti-ambitionates, rendering the preparation obsolete.
UPDATE: Happy Birthday to Karma!