The present invention relates to a composition for preventing or reducing microbial growth, particularly the growth of dermatophytic fungi, and/or aciduric and acidogenic gram-positive bacteria. More particularly, it relates to the use of trans-3,5,4′-trihydroxybibenzyl, also known as dihydro-resveratrol, or its dihydrostilbene derivatives and/or chemical variants as an anti-microbial agent. The present invention further relates to the management of dermatophytosis often caused by dermatophytic fungi and the management of dental caries often mediated by aciduric and acidogenic gram-positive Streptococci. The present invention therefore has applications in preventing, alleviating and/or treating dermatophytosis and dental caries.