Sodium butyrate—more properly sodium butanoate—is a salt of butyric (butanoic) acid. If it comes into contact with even a trace of moisture, it emits a faint odor of its foul-smelling conjugate acid.

Butyric acid goes by several other names, including butyrate and butanoic acid. You’ve likely heard that eating fiber is good for your digestion. Part of the reason why eating more fiber may ...