In a population of plant meristematic cells of Vicia faba the frequency of sister chromatid exchanges (SCEs), incidence of chromosomal aberrations and mitotic activity of cells was evaluated after short-term treatment (1 h) with antitumour active platinum complexes cis-DDP, CHIP IV, CBDCA, oxo-Pt and antitumour inactive trans-DDP. It was found that the action of platinum compounds in equimolar concentration 3.33 microM increases the level of SCEs 1.3 to 6.4-fold. The maximum effect in terms of SCE formation was observed after cis-DDP. Comparison of the incidence of SCEs and chromosomal aberrations in plant cells demonstrated that the tested drugs had a greater effect on SCE formation than on chromosomal aberration induction. Inhibition of mitotic activity correlated with the total cytogenetic damage to chromosomes of Vicia faba cells.