One of the most important roles of Ca in plants is that of protecting against toxicities of trace metals. Even though this is a function of Ca, at least some of the trace metals in excess do inhibit uptake and/or translocation of Ca. Managanese, when supplid at a very high level to bush beans (Phaseolus vulgarisL. cultivar Improved Tender‐green) in solution culture, decreased Ca concentration in leaves, stems, and roots. The inhibition was pronounced for 10(E‐3) and 10(E‐2)MMn. The decrease for the latter was 76% for leaves, 61% for stems, and 49% for roots. Molybdenum at 10(E‐3)Mdecreased bush bean leaf, stem, and root concentrations of Ca by 38%, 24%, and 16%, respectively. Vanadate at 10(E‐5) M decreased bush bean concentrations of Ca in leaves, stems, and roots by 37%, 50%, and 11%, respectively. Silver at 10(E‐5)Mdecreased Ca in leaves by 67%. Cadmium at 10(E‐4)Mdecreased leaf, stem, and root Ca by 76%, 28%, and 61%, respectively. Lithium at 50 ppm in soil decreased yields of bush beans by 75%, but had no effect on Ca in the shoots. In soil, 500 ppm Li decreased shoot yield of barley (Hordeum vulgare L. cultivar Atlas 57) by 66% and Ca concentration by 72%. Nickel (2 X 10(E‐5)M) decreased Ca concentration in bush bean leaves by 45% at 10(E‐4)MCa, 42% at 10(E‐3)MCa, and 33% at 10(E‐2)MCa. In roots the reductions were 35%, 43%, and 44%, respectively. Decreased uptake of Ca caused by excess trace metals could increase their phytotoxicity.