In the United States and perhaps elsewhere, there is a common misconception that the poinsettia is highly toxic. This misconception was spread by a 1919 urban legend of a two-year-old child dying after consuming a poinsettia leaf.

While the sap and latex of many plants of the spurge genus are indeed toxic, the poinsettia's toxicity is relatively mild. Its latex can cause an allergic reaction in sensitive individuals. It is also mildly irritating to the skin or stomach and may sometimes cause diarrhea and vomiting if eaten. Sap introduced into the human eye may cause temporary blindness. An American Journal of Emergency Medicine study of 22,793 cases reported to the American Association of Poison Control Centers showed no fatalities, and furthermore that a strong majority of poinsettia exposures are accidental, involve children, and usually do not result in any type of medical treatment. POISINDEX, a major source for poison control centers, says a 50-pound child would have to eat 500 bracts to accumulate levels of toxins found to be harmful in experiments. An Ohio State University study showed no problems even with extremely large doses.

Albert Ecke emigrated from Germany to Los Angeles in 1900, opening a dairy and orchard in the Eagle Rock area. He became intrigued by the plant and sold them from street stands. His son, Paul Ecke, developed the grafting technique, but it was the third generation of Eckes, Paul Ecke, Jr., who was responsible for advancing the association between the plant and Christmas. Besides changing the market from mature plants shipped by rail to cuttings sent by air, he sent free plants to television stations for them to display on air from Thanksgiving to Christmas. He also appeared on television programs like The Tonight Show and Bob Hope's Christmas specials to promote the plants.

The poinsettia (Euphorbia pulcherrima) is a culturally and commercially important plant species of the diverse spurge family that is indigenous to Mexico and Central America. It is particularly well known for its red and green foliage and is widely used in Christmas floral displays. It derives its common English name from Joel Roberts Poinsett, the first United States Minister to Mexico, who introduced the plant into the United States in 1825.