Throughout the world, there are over 400 species of holly plants. Although edible to some birds and other animals, holly berries are not edible for humans and should not be consumed.
For humans, eating more than three holly berries can cause prolonged nausea, vomiting, diarrhea and drowsiness. Holly berries are considered more harmful to children, but are not considered fatal. If you have ingested holly berries and are experiencing an adverse reaction, contact the nearest poison control center.
Ilicin is the toxic principle in many holly berries. Some species, like the English holly, contain the toxin theobromine in the leaves and berries of the plants. Regardless of which type of holly is consumed, ilicin and theobromine produce nausea, vomiting, drowsiness and diarrhea when ingested in quantity. Ilicin is also known to cause dermatitis.
Holly berries are red, black, orange or yellow. Holly is found in many areas across the world. Species of holly are found in Europe, the Mediterranean, North Africa, Asia, Northern Iran, North America and Australia.