Abstract The anti-inflammatory potential of marjoram and sweet basil essential oils obtained by supercritical fluid extraction (SFE) was tested in vitro using THP-1 human macrophage cells. THP-1 cells were activated by lipopolysaccharide or human ox-LDL and the cytokine secretion and gene expression of, respectively, TNF-α, IL-1β, IL-6 and IL-10 along with COX-2 and NFκB gene expression was evaluated. Results indicated that both marjoram and sweet basil essential oils at a concentration of 10 μg/mL markedly suppressed the production of pro-inflammatory cytokines and gene expression in LPS and ox-LDL THP-1 activation. The chemical composition of marjoram and basil extracts was evaluated and the activity of the main compounds was also tested for cytokine production and gene expression. We concluded that the anti-inflammatory activity of both oils is dedicated to their main compounds, respectively, sabinene hydrate and terpineol for marjoram and linalool and eugenol for sweet basil extracts. Furthermore, these results confirmed their application as anti-atherosclerotic agents. Main compounds presented in supercritical basil (linalool and eugenol) and marjoram (sabinene hydrate and terpineol) essential oils also presented an important anti-inflammatory activity, which allowed us to propose these compounds as responsible for the anti-inflammatory activity found in essential oils. In conclusion, SFE allowed to obtain sage and marjoram essential oils with significant anti-inflammatory properties. Furthermore, these supercritical essential oils have also shown an important anti-inflammatory effect in an atherosclerotic environment and presented a highly potential application in the prevention of atherosclerosis.