Toxicity refers to the degree to which a substance can cause harm to living organisms. This can include chemicals, plants, or even certain types of food. The harmful effects can range from mild irritation to severe health issues, depending on the dose and exposure level. Understanding toxicity is essential in fields like medicine, environmental science, and safety regulations. Different substances have varying levels of toxicity. For example, carbon monoxide is highly toxic and can be fatal in high concentrations, while water is generally safe but can be harmful in excessive amounts. Evaluating toxicity helps in assessing risks and ensuring safety in everyday life.