Introducing students to the process of scientific inquiry is a major goal of high school and college labs. Environmental toxins are of great concern and public interest. Modifications of a vertebrate developmental toxicity assay using the frog Xenopus laevis can support student-initiated toxicology experiments that are relevant to humans. Teams of students formulate hypotheses, perform experiments, analyze data, and present their results. By performing experiments to investigate the toxicity of household chemicals, pharmaceuticals, or agricultural chemicals, students will gain an appreciation of the environmental effects of improper disposal of common chemicals and industrial or agricultural run-off.