Technicians purify, dry, and freeze the venom. A weakened solution of the venom is injected into a horse, pig, or other animal, which produces immune-system cells called antibodies in reaction. In essence, the animal becomes a drug factory. The antibodies are extracted from the animal's blood, then processed into the antivenom. When a bite victim arrives at the hospital, doctors inject the antivenom, helping the body's own immune system ward off the poison.
Physicians have to be careful, however, since some people can react badly to antivenom.
Venom is studied for its medicinal properties. Antivenom isn't the only medical use of venom. Researchers also study venom because it contains dozens of substances that may be of medicinal value. At the University of Buffalo, New York, for instance, a protein isolated from the venom of a Chilean tarantula is being used to develop a new drug to treat atrial fibrillation, the chaotic beating of the heart that is a major cause of death following a heart attack. The work is an unexpected outgrowth of basic studies of the venom.