Holiday Plant Hazards

As the holiday season rolls around, an age-old debate over safety of festive foliage resurfaces. Is the poinsettia poisonous? Are holly berries harmful? Is mistletoe medicinal or will it make a person ill? Holly, mistletoe and the poinsettia are three holiday favorites. Small children, dogs and cats find these plants to be a favorite attraction as well. This article will attempt to dispel the myths and make known the facts regarding the toxicity associated with these plants.

The poinsettia was introduced in the U.S. in the early 1800s by Joel R. Poinsett, the American ambassador to Mexico. Since 1919, the poinsettia has been one of the most feared household plants. That year, in Hawaii, a doctor mistakenly attributed the death of an Army officer’s two-year-old daughter to her ingestion of a poinsettia leaf. The story has been handed down for generations and old legends dies hard1.

Today scientists have proven that the poinsettia plant is not poisonous. Numerous studies have been performed in rats that tolerated ingestions of up to 50g of poinsettia per kg of body weight.2 That is the same as saying the rats tolerated "doses equivalent to a 25-pound, two-year-old child eating about 250 poinsettia leaves in one day."1 Eight years worth of data, with 22,793 human-poinsettia exposures, collected by participating poison control centers, was published through a grant from the American Association of Poison Control Centers (AAPCC) in a 1996 article. Most subjects of the study were children (93.3 percent), a majority of which were under the age of two years old (77 percent). The study showed that there were no poinsettia-related deaths, and 92.4 percent of the cases had no reported effects. Of those that did have an effect, stomach irritation was the most common. It was also found that using decontamination methods, such as ipecac, had no impact on patient outcomes.3 Finally, a 1998 report on pet ingestion of poinsettias showed that 15 dogs had ingested poinsettias, with three becoming ill — vomiting and diarrhea. Of the 51 cats in the report that ingested poinsettias, one was reported to have the side effect of excessive salivation.2

These data appear to support the claim that the poinsettia plant is non-toxic and at worst a stomach irritant. However, it is an ornamental plant that should not be eaten by people or pets. Therefore, it should be kept out of the reach of curious little ones.

American mistletoe is another plant with a mythical and magical history, which is actually associated with the abundance of literature published about European mistletoe. Both types of mistletoe are a parasite of woody plants. It has been thought that this parasitic activity can go so far as to leech the body of its ills. Such speculated benefits of the European mistletoe are control of excess bleeding after childbirth, treatment of cholera, calming of nervousness and treatment of cancer – none of which are proven. However, European mistletoe has been attributed to toxicity with medicinal use as well as fatalities. American mistletoe has been assumed guilty by association. The two species are grossly similar in looks; however, the European mistletoe is not indigenous to the U.S. and is only cultivated in isolate areas of the U.S. Furthermore, it is not available for commercial sale.4

Several studies have been done to determine what American mistletoe ingestion is guilty of causing. In a 1997 study produced by the AAPCC, 1754 exposures to American mistletoe were reported with almost 80% of the cases being managed without referral to a healthcare facility, 90.3 percent of the victims had no symptoms when the final outcome was determined. None of the exposures of the study were fatal.5 In another study conducted by Spiller et al, with exposures of up to five leaves and 20 berries, only 12 percent of 92 exposures had any symptoms reported.4

American mistletoe has been associated primarily with stomach upset (nausea, vomiting and diarrhea). There have also been cases reported of mild drowsiness, eye irritation, ataxia, seizure and choking after aspiration of berries.5 One death following the ingestion of tea brewed from American mistletoe berries was reported. This patient suffered severe stomach irritation and cardiovascular collapse.6 However, the plant known for standing under to steal a kiss is unlikely to be "the kiss of death." It is important to keep this holiday beauty out of the reach of small children and pets, and to pick the leaves and berries up off of the floor immediately, if they fall.

Another popular plant of the season is holly. In Brazil holly plants were once brewed into teas and used as a drink for ceremonially "cleansing." Its cleansing actionwas  attributed to sweat and vomit-inducing effects. The toxicity of holly is most notably defined by stomach disturbances resulting from ingestion of the berries. Often nausea and vomiting can be prolonged. Diarrhea has been reported to be bloody at times.7

One case reported two-year-old twins ingesting a handful of berries. Each child vomited for over six hours, and one became drowsy 20 hours after ingestion. Each child had diarrhea.7 Prolonged vomiting may lead to electrolyte imbalances. Another reported ingestion of 20 to 30 berries in a two-year-old child resulted in death.8 Size of ingestion influences the degree of toxicity. Ingestion of small amounts of berries may not cause any effects at all. The leaves of most species are considered to be non toxic, though they do have sharp spines which may be of concern.6 Like the berries of the mistletoe plant, holly berries carry the risk of aspiration.

Small children and pets find the red berries of this plant to be especially intriguing. Therefore it is important to promptly pick up any that may fall to the ground from a household plant. Likewise, it is important to keep them out of the reach of fascinated children and curious animals.

In cases of ingestion of any holiday hazards, don't hesitate to call your poison control center. In Texas, the number for poison control is 800-222-1222.

  1. Koschier, F. The myth of the ‘poisonous’ poinsettia. American Council on Science and Health. 2000; Dec 12.
  2. Hornfeldt, C.S. Confusion over toxicity of poinsettia. J Am Vet Med Assoc. 1989 Apr 15; 194 (8):1004.
  3. Krenzelok, E.P. Poinsettia exposures have good outcomes…just as we thought. Am J Emerg Med. 1996 Nov; 14 (7): 671-4.
  4. Krenzelok, E.P. American mistletoe exposures. Am J Emerg Med. 1997 Sep; 15(5): 516-20.
  5. Spiller H.A. et al. Retrospective study of mistletoe ingestions. Clin Toxicol 1995; 33: 545.
  6. Baker, M.D. Holiday hazards. Pediatr Emerg care. 1985 Dec; 1 (4): 210-4.
  7. DerMarderosiam A (Ed): Facts and Comparisons – The Review of Natural Products. Topic: Holly, St. Louis, MO, 1996.
  8. Ellis M.D. Hosp Phys 1972 Dec 2; 42-3.

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