the analysis of the antimicrobial activity of the essential oil of sida cordifolia was evaluated with four different strains of bacteria and nine fungi. the essential oil was tested "in natura" (100 %) and diluted from 32 until 2 %. the microorganisms, bacteria and fungi, were spread in agar muller-hinton and sabouraud dextrose, respectively. s. cordifolia showed inhibitory activity against the microorganisms tested with efficacy of 80 %. when tested against staphylococcus aureus, staphyllococus epidermidis, candida guilliermondii and trichosporon inkin the essential oil showed the best performance.