Summary Background Microsporum spp. are keratinophilic dermatophytes that mainly invade the stratum corneum of the skin and hair causing clinical symptoms associated with tinea . Its treatment has several limitations, and the search for new active molecules is necessary. Objective To evaluate the antifungal and cytotoxic potential of Eugenia caryophyllus essential oil ( EO ), eugenol, isoeugenol and methylisoeugenol against Microsporum canis , M . gypseum and Vero cells. Methods The EO was extracted by conventional heating‐assisted hydrodistillation, the eugenol obtained commercially and the derivatives through Williamson synthesis. Minimal inhibitory concentration ( MIC s), minimum fungicidal concentration, inhibition of radial mycelial growth and germination inhibition were used to evaluate the antifungal activity. In addition, a colorimetric test was conducted to evaluate cytotoxic activity. Results MIC and MFC values for all compounds were 62.5‐500 μg/mL for both of the species of Microsporum evaluated. Also, concentrations of 300 μg/mL of the compounds inhibited 100% of M . canis mycelium. The inhibition of germination was observed after 6 hours of treatment (11.86 ± 3.46‐85.31 ± 0%). No cytotoxicity was observed in Vero cells ( CC 50 > 105 μg/mL), whereas terbinafine showed CC 50 31.00 ± 0.61 μg/mL. Conclusions Our study indicates an interesting bioactivity of isoeugenol and methylisoeugenol against M . canis , M. gypseum and mammalian cells.