Natural substances can treat cancer, prolong life and trigger amazing hallucinations.

But although nature can make a remarkably wide variety of chemicals — far more than the best molecule-making robots — it does not always deliver them in bulk. Drug companies and medical researchers often turn to organic chemists when they need something that is too rare or too difficult to harvest from the wild.

Many researchers enjoy the challenge of building complicated molecules from scratch in their laboratories, testing their skills in service of a worthwhile goal. Duplicating Mother Nature isn't easy, and sometimes the journey is almost as impressive as the chemicals themselves.

http://www.wired.com/science/discoveries/multimedia/2009/01/gallery_nature_chemicals