COLUMBIA, Mo. – Use it to steal a kiss, but keep it away from children, pets and yourself. Every part of mistletoe, an evergreen plant with white berries, is highly toxic.

“Mistletoe from the United States (Phoradendron leucarpum) contains phoratoxin, which is found in all parts of the plant,” said David Trinklein, horticulture specialist for University of Missouri Extension. “While mistletoe harvested in the U.S. isn’t as toxic as European mistletoe (Viscum album), if any part of either plant is ingested it would be wise to seek immediate medical attention.”

In any case, Trinklein said, mistletoe isn’t usually labeled “American” or “European,” and only a trained botanist could tell them apart. He said the safest choice is to use artificial mistletoe made from silk or plastic.

Mistletoe is hemiparasitic, meaning it gets some of its food from its host, most often a tree, while also using photosynthesis to make its own food, Trinklein said.

How did a toxic, hemiparasitic plant like mistletoe become a part of Christmas? Trinklein says human use of mistletoe has a long and interesting history. Many ancient cultures considered mistletoe sacred and believed it had mysterious powers. Perhaps it was because of the latter that druid elders harvested mistletoe as a winter solstice ritual, he said. When these ancient people converted to Christianity, the use of mistletoe somehow continued and, over the years, it became a part of Christmas tradition.

How did kissing under the mistletoe originate?

“Varies theories exist. One of the more popular ones, from Norse legend, said that mistletoe in the house would keep warring spouses from becoming too belligerent toward each other,” Trinklein said. “According to the legend, each time a kiss was exchanged under the mistletoe, a berry had to be plucked. Once all the berries were gone it lost its magic.”

The word “mistletoe” is derived from two Anglo-Saxon words that, literally interpreted, mean “dung twig,” Trinklein said. This less than tidy name came after people observed that mistletoe tended to take root on tree limbs where birds left their droppings.

Perhaps it’s best to forget about the origin of the name and just enjoy the kisses when you can get them.