Abstract Objectives The immunomodulatory effect of ginger, Zingiber officinale (Zingiberaceae), sage, Salvia officinalis (Lamiaceae) and clove, Syzygium aromaticum (Myrtaceae), essential oils were evaluated by studying humor- and cell-mediated immune responses. Methods Essential oils were administered to mice (once a day, orally, for a week) previously immunized with sheep red blood cells (SRBCs). Key findings Clove essential oil increased the total white blood cell (WBC) count and enhanced the delayed-type hypersensitivity (DTH) response in mice. Moreover, it restored cellular and humoral immune responses in cyclophosphamide-immunosuppressed mice in a dose-dependent manner. Ginger essential oil recovered the humoral immune response in immunosuppressed mice. Contrary to the ginger essential oil response, sage essential oil did not show any immunomodulatory activity. Conclusions Our findings establish that the immunostimulatory activity found in mice treated with clove essential oil is due to improvement in humor- and cell-mediated immune response mechanisms.