Indole at high concentration is commonly described as smelling like?

• A. Vanilla
• B. Chocolate
• C. Feces
• D. Mint

Answer: (C)

Indole’s smell changes with concentration. In nature, it’s a volatile compound produced by certain bacteria breaking down tryptophan, and the odor you notice depends on how much is present. At low concentrations, indole can carry a subtle, sometimes floral or jasmine-like nuance. But when the concentration is high, the scent becomes strongly foul and is commonly described as resembling feces. That shift from a lighter, almost pleasant note to a harsh, putrid odor is why high levels of indole are characterized as smelling like feces. The other descriptors—vanilla, chocolate, mint—are associated with different compounds and do not reflect indole’s typical high-concentration odor.