Myths and rumors about the toxicity of the poinsettia plant are common late in the year, when the popular red-leaved plants take center stage in holiday decorations. While the genus (Euphorbia) to which the poinsettia plant belongs does contain some highly toxic plants, the popular poinsettia itself is not toxic. Some sources attribute the rumor about the dangers of poinsettia leaves to a case of poisoning in 1919 that led to the death of a two year-old child. At the time, the cause of the poisoning was incorrectly determined to be a poinsettia leaf.
Contact with the sap of a poinsettia plant may cause a mild, itchy
rash. If this happens, wash the affected area with soap and water
and apply a cool compress to ease itching. Eating the leaves or
stems of a poinsettia plant may cause a mild stomachache, vomiting
or diarrhea, but severe signs and symptoms are unlikely.
A 50 pound child would need to eat about 500-600 leaves or about 20
ounces of the bitter tasting leaves of a poinsettia plant before any
medical action would be necessary.