Given the epidemic of rhino poaching across Africa and Asia, which has placed four out of five species in jeopardy of extinction, one fed-up game manager wants to take the fight beyond the poachers to the consumer. Ed Hern, owner of the Lion and Rhino Park near Johannesburg, told South Africa's The Times that he has begun working with a veterinarian on injecting poison into a rhino's horn to consumers. He told The Times that people who consumed poisoned rhino horn "would get very sick or die".
Unlike the consumer, the rhino likely wouldn't be hurt by the poison, since their was no blood flow from the horn into the rest of the animal. Still Hern was watching his test rhino to make sure it wasn't showing symptoms. Hern has been warned by unnamed lawyers that he could get "into a lot of trouble" if someone is harmed by ingesting rhino harm that was poisoned.
Banned worldwide by the Convention on International Trade in Endangered Species (CITES) rhino horn is used as a traditional curative in Chinese medicine. While scientific studies have shown that rhino horn has no medicinal properties, it remains in high demand fueling the violent and illegal trade of rhino poaching.
In the last six months, South Africa has lost 124 rhinos to poachers. Ed Hern—on the frontlines of the poaching battle—has taken in five rhino orphans whose mothers were killed. Hern pays private guards to protect his rhinos, but says they are no match against the hi-tech equipment, including helicopters, used by the wildlife trafficking mafia.
EDIT
http://news.mongabay.com/2010/0728-hance_poison_rhino.html