The berries on holly bushes are poisonous. Consumption of the berries can cause dehydration, vomiting, diarrhea and even death. In addition to the berries, holly leaves are also unsafe to eat. They can also cause stomach problems, and the sharp leaves can cut into the mouth and the digestive tract.
The holly plant comes in a variety of species. English holly, Oregon holly and American holly are commonly used to make Christmas decorations. The leaves of other types are used to make medicines and treat disorders such as cough, high blood pressure, jaundice, joint pain, chest congestion and heart disease.