Guaiacum

Medical students hate the idea that a patient needs a "guaiac." The stool guaiac test is as important as it is unpleasant. It is designed to detect to presence of occult blood in stool. The duty often falls upon the medical student to do the rectal exam and check for blood. Almost all patients who present to the emergency department get guaiac'd, simply to make sure they aren't bleeding.

One of my co-interns looked into the origin of this test, and it was fascinating. The word "guaiac" comes from guaiacum, a genus of flowering plants that has a host of crazy uses. The genus supplies some of the hardest wood; gum made from the wood was once used to treat syphilis; wood chips make a tea; a derivative is a common medication for cough called guaifenesin; sometimes you see ornamental plants from this family. And I had thought it was only a fecal occult blood test.

First image of the stool guaiac test shown under Creative Commons Attribution Share-Alike License, from Wikipedia. Second image of the flower from Wikipedia, in the public domain.