Short chain fatty acids (SCFAs) and glycerol esters of SCFAs not previously used for that purpose are provided for use as a medicament for treating, preventing or counteracting microbial infections in animals, including humans, by stimulating the innate antimicrobial peptide defense system. Preferred compounds include phenyl substituted short chain fatty acids (SCFAs) derivatives and. Also provided are methods and compositions for treating, preventing or counteracting microbial infections, including bacterial, viral, fungal, and parasitic infections, by administration of medicaments comprising a secretagogue-effective amount of the compounds of the invention.