Eating small amounts of chalk is usually not harmful, according to MedlinePlus. Chalk, a form of limestone, is not normally toxic, but when consumed in large quantities, problems can occur.
A person who eats a large amount of chalk can experience digestive symptoms, such as pain in his abdomen, nausea, vomiting, diarrhea or constipation, states MedlinePlus. He can also exhibit respiratory symptoms, such as coughing and shortness of breath.
When a person consumes chalk either intentionally or accidentally, it is best to call the Poison Control Center for advice, says MedlinePlus. Seek emergency medical assistance if necessary. Medical personnel can monitor temperature, pulse, blood pressure and rate of respiration and treat abnormalities as necessary. Most people recover from ingesting chalk, but their reactions and prognoses depend on the amount of chalk consumed and the speed at which treatment begins.