Chalk (Blackboard, Sidewalk)

What is it?
First Aid
Safety Tips

Writing on a blackboard with chalk

What is chalk?

Chalk is a product used for writing or drawing that is most often made of the mineral gypsum (calcium sulfate). Less commonly it is made from a rock that is known as chalk (calcium carbonate).

Products like blackboard chalk and sidewalk chalk are not very harmful to swallow, but can be a choking hazard.

What happens if you swallow chalk?

Eating or swallowing a small piece of chalk may irritate the mouth and throat, and can occasionally cause an upset stomach. It may also cause a chalky color and consistency in the stool.

Swallowing a larger piece of chalk may make the person choke or gag.

What happens if you breathe in chalk dust?

Breathing in dust from chalk can mildly irritate the nose and throat.

Dust may also irritate the eyes.

What should I do if someone has swallowed chalk?

In most cases, a little bit of water to rinse out the taste and a snack to settle the stomach is all the person needs.

If the person is coughing or throwing up, call the poison center at 1-800-222-1222, chat online or text POISON to 85511.

How can I use chalk safely?

Even though chalk is not very harmful, it can still be a choking hazard. Some companies make larger pieces of chalk that are safe for young children. Keep smaller pieces of chalk and other items with small parts out of the reach of young children.

Last Updated: Tuesday September 6th 2016