Toxicity testing is a scientific process used to determine the harmful effects of substances on living organisms. This testing helps identify whether chemicals, drugs, or environmental pollutants can cause adverse health effects, such as illness or death. Various methods, including laboratory experiments and computer simulations, are employed to assess toxicity levels. The results of toxicity testing are crucial for regulatory agencies, such as the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA), to ensure public safety. By understanding the potential risks associated with different substances, these organizations can establish guidelines and regulations to protect human health and the environment.