complex type of odor resembling that of the waste matter discharged from the bowels, influenced by dietary and endogenous contributions. Major components are sulfurous (hydrogen sulfide: odor of rotten eggs, butyl mercaptan: skunk, methyl mercaptan: rotting cabbage, sweaty feet), nitrogen, phosphorous and heterocyclic organic compounds such as indole (napthalenelike "mothball" odor) and scatole (3-methylindole produced from tryptophan in the digestive tract, classical "fecal odor"), ammonia and trimethylamine. Fatty acids contributing to smell include Acetic and Propionic acids (vinegar), Butyric acid (rancid butter), and Valeric acid (cheesy and sweaty). These chemicals occur as part of the normal digestive processes in all mammals. The diet, and the configuration of digestive system determine the types and amounts of the very large number of possible odoriferous substances in feces, and so are diseases and conditions. Obese individuals, for example, have more ester compounds, hydrogen sulfide is increased in Ulcerative Colitis, and fruity-alcoholic-fermented-smelling aldehydes are increased in Celiac disease. Colorectal cancer patients have higher levels p-hydroxy-benzaldehyde (woody odor), IBS with diarrhea increases esters of short chain fatty acids and cyclohexanecarboxylic acid (fruity and cheesy). Fecal breath odor can indicate certain types of intestinal blockage.
