A five day, whole plant toxicity test was developed and evaluated. The eighteen chemicals tested were primarily substituted benzenes and phenols, although representative herbicides, surfactants, and other industrial chemicals were also tested. The test yields information on root and shoot growth as a function of toxic chemical concentration in the root environment and can also be used to determine effect on transpiration. The measurement found to be the most sensitive indicator of toxicity was total plant growth. EC50 values were estimated for each compound using regression analysis. The simple bioassay gives a quick response to an acute exposure and can be used to screen chemicals at various concentrations.