The Houston Zoo’s blog has a solid post that summarizes how and why amphibians hold the key to new medicines:

More than 200 beneficial chemicals known as alkaloids have been extracted from frog and toad skin. For the amphibians, these poisonous alkaloids serve as a natural chemical defense, affecting the muscles and nerves of predators.   Medical research, however, has uncovered numerous beneficial uses for these same substances.  One alkaloid produced by amphibian skin is a highly effective painkiller, 200 times stronger than morphine.  Yet it is not addictive like morphine. Skin secretions from the green treefrog have been shown to stimulate activity in the human pancreas and intestine, and commercial drugs are now available based on these compounds. The large parotoid glands of toads, located just behind the eyes, produce two substances that affect the adrenal and cardiovascular systems in humans. A third secretion from these same glands is a powerful hallucinogen.  Further research may very well yield new medicines from these compounds.


Frog skin secretions also can have powerful antibiotic properties. The skin of the African clawed frog, once again, produces protein-like chemicals called  peptides that help heal cuts and bruises, which may provide doctors with a whole new class of antibiotics in the years ahead. Research suggests that skin secretions of some frogs may also help repair human internal organs following surgery.