The cytotoxic effect of chemicals on cells in culture is measured by the change in total cell protein (Kenacid Blue R dye binding method). Healthy 3T3-L1 cells (an established cell-line, ATCC CCL92.1), when maintained in culture continuously divide and multiply over time. The basis of this test is that a cytotoxic chemical (regardless of site or mechanism of action) will interfere with this process and, thus, result in a reduction of the growth rate as reflected by cell number. The degree of inhibition of growth, related to the concentration of the test compound, provides an indication of toxicity.