The methanol extracts (3.3, 5.6 and 10.0%) of Berberis vulgaris L., Mentha longfolia (L) Huds., Salvia limbata C.A. Mey., Artemisia absinthium L., Achillea biebersteinii Afan., Origanum vulgare L., Medicago sativa L., Vicia cracea (Desf.) B. Fedtsch were applied to maize (Zea mays L.) seeds to determine their effects on radical, plumule growth, contents of phytohormones [giberellic acid equivalents (GAs), indole-3-acetic acid (IAA), trans-zeatin (t-Z) and abscisic acid (ABA)], carbohydrates (glucose, fructose and sucrose), fatty acids, (palmitic acid and oleic acid), mitotic index and chromosome abnormalities as compared to control. The 5.0 and 10.0 % extracts inhibited the germination. The extracts also decreased the length of plumule and radicals. However, there were variable effects on plant hormones, fatty acids and sugar levels. Plant extracts decreased the mitotic index and also caused abnormalities in chromosomes.