Four commonly used spices plants in Iran were evaluated for cytotoxicity effect using Brine Shrimp Lethality (BSL) assay. Essential oils and various extracts of Heracleum persicum, Nigella arvensis, Cinnamomum zeylanicum and Zingiber officinale were assessed by two methods of disk and solution of BSL. Data were processed in probit-analysis program to estimate LC50 values. All of the tested fractions have exhibited more cytotoxicity in the solution method. Essential oils of H. persicum and C. zeylanicum have shown the most cytotoxicity with LC50 values 0.007 and 0.03 microg/ml respectively. None of aqueous extracts showed significant cytotoxicity. The analysis of the essential oil of H. persicum showed the hexyl butyrate and octyl acetate as the main compounds. These results suggest some limitation for using of these spices in diet. Furthermore, these plants could be considered as a source of cytotoxic compounds which might be studied in more details.