Nontoxic means not poisonous or harmful to living things. A nontoxic marker won't make you sick if you accidentally get some on your hands or even in your mouth. Nontoxic glue is safe for kids to use in art projects because it won't hurt them if they touch it or breathe in its fumes.

When you see “nontoxic” on a product label, it tells you that the manufacturer has tested it to make sure it won't poison people or animals under normal use. This matters especially for things young children might put in their mouths, like crayons or play dough.

Scientists and safety experts have specific standards for what counts as nontoxic. A substance might still taste bad or cause minor irritation without being toxic. For example, soap is generally nontoxic, but you still wouldn't want to eat it.

The word also gets used more loosely to describe environments or relationships. Someone might talk about creating a nontoxic classroom where students feel safe and respected, or having nontoxic friendships where people treat each other kindly. In these cases, nontoxic means healthy and supportive rather than literally “not poisonous.”