If you were looking forward to poisoning your loved ones and playing it off as a holiday accident, don't look to the poinsettia to lend a hand. The famously "poisonous" seasonal flowers are not poisonous at all.
Poinsettias are the big ugly red flowers often associated with Christmas. As a child, I was always warned away from them, because everyone knew they were poisonous. Turns out, they're nothing of the kind. The rumour that these flowers were poisonous got started in 1919. According to a popular story, an Army officer posted in Hawaii was enjoying a tropical Christmas with his family when one of his children ate poinsettia leaves and died.
It was 1972 before anyone decided to follow up on the story by contacting the hospital where the death supposedly occurred. The doctor involved had passed away, but his son was available for comment and stated for the record that the story of death-by-poinsettia was nonsense.
To be sure, in 1971 doctors tested out poinsettias as a poison. They blended leaves into a smoothie and fed it to rats. The rats gobbled down the leaves and remained as healthy as any lab rat could ever hope to be. The most enthusiastic rat downed the equivalent of a human eating 600 poinsettia leaves. It felt no ill effects. Doctors concluded that kids would have to eat over a pound of leaves to get an equivalent dose that the rats consumed.
Scientists repeated the experiment in 1980. Forty-six rats were fed poinsettias, observed, then "sacrificed." The scientists found "no changes in behaviour," no changes in weight, and no lesions on any of the organs inside the rats. One group of rats had a significant increase in thyroid weight, but most of them were absolutely fine.
Putting the final nail in the coffin lid of the theory, a review of over 20,000 cases of poinsettias found no fatalities.
So those of you hoping to knock off your relatives when you go home for the holidays, look for some other type of poison to slip into their drinks. Or just send a card.