The present invention provides the use of allicin in (i) the treatment of leishmaniasis; (ii) as a disinfectant or biocida treatment of aquatic species; (iii) as an antimicrobial agent for animal feed; (iv) as a preservative agent in foodstuffs; (v) as a water disinfectant or biocide; (vi) as an antiparasitic treatment or antibacterial treatment for bees (apis); or (vii) in the preparation of a medicament for the treatment of Glycopeptide Intermediate Resistant Stapohylococcus Aureus.