The smell of fecal matter after death is persistent with which combination?

• A. Skatole and Indole
• B. Cadaverine and Putrescine
• C. Ammonia and Ammonium compounds
• D. Hydrogen sulfide and Methane

Answer: (A)

Fecal odor during decomposition comes mainly from indolic compounds produced by gut bacteria breaking down amino acids, especially tryptophan. Indole and skatole have strong, characteristic fecal smells and they persist as decomposition continues, making the odor lasting. The other compounds contribute different odors: cadaverine and putrescine create a general putrid smell from amino acid decarboxylation, ammonia and ammonium compounds give a sharp, ammonia-like odor, and hydrogen sulfide adds a sulfurous rotten-egg scent (with methane being odorless). Because indole and skatole specifically produce the fecal smell and persist, they are the best explanation.