guaiacListen to pronunciation(GWY-ak)A substance from a type of tree called Guaiacum that grows in the Caribbean. Guaiac is used in the fecal occult blood test (a test for blood in human stool samples).More InformationScreening Tests to Detect Colorectal Cancer and PolypsSearch NCI's Dictionary of Cancer TermsStarts withContainsBrowse:ABCDEFGHIJKLMNOPQRSTUVWXYZ#
