Smyrnium olusatrum essential oils were evaluated against Trypanosma brucei. Their inhibitory activity was noteworthy (IC50 range was 1.9–4.0 μg/ml). The most active oil component was isofuranodiene (IC50 0.65 μg/ml). β-Acetoxyfuranoeudesm-4(15)-ene increased the parasite sensitivity. Germacrone was ineffective against the parasite.