Nickel, a major environmental pollutant is known for its clastogenic and carcinogenic potential. Dietary inhibitors of mutagenesis and carcinogenesis are of particular importance since they may have a role in cancer prevention. In the present investigation, aqueous extract of edible dried fruits of Phyllanthus emblica, a well known medicinal was fed to Mus musculus for seven consecutive days prior to treatment with different doses of nickel chloride (10, 20 and 40 mg/kg body wt.); the fruit extract significantly reduced the frequency of CA/cell, the percentage of aberrant cells and the frequency of micronuclei induced by all doses of nickel in the bone marrow cells of mice. Ascorbic acid, a major constituent of the fruit, fed for 7 consecutive days in equivalent concentration as that present in the fruit, however, could only alleviate the cytotoxic effects induced by low doses of nickel; at the higher doses it was ineffective. The greater efficacy of the fruit extract could be due to the interaction of its various natural components rather than to any single constituent. The study assumes importance in view of the widespread human exposure to nickel compounds. © 1991.