The Poison Control Center

Plants That Irritate

The following plant groups are classified as irritants of the skin or gastrointestinal tract. Oxalates irritate both the skin and the gastrointestinal tract. Exposure to small amounts of these plants is relatively safe.

Oxalates (mouth irritants)

Oxalate plants contain sharp, tiny crystals in their juices, leaves and stems, called calcium oxalate crystals. Oxalate crystals can cause intense pain and swelling if they come in contact with the skin or mouth.

When any part of these plants is chewed and swallowed, the crystals stab the sensitive tissues of the tongue, gums and throat, creating the sensation of biting into ground glass. Pain, difficulty swallowing, swelling and temporary hoarseness may occur.

Poisoning from swallowing an oxalate-containing plant is rare because the intense mouth pain usually prevents children from eating a significant quantity of the plant.

If a child eats any part of an oxalate-containing plant, wipe out the residue of the plant from the mouth and offer a cool drink or snack such as a popsicle, applesauce or yogurt. If there is swelling that prevents the child taking anything by mouth or causes difficulty breathing, go to the nearest emergency department immediately.

When the juices of the plant come in contact with the skin, burning, pain and swelling may occur. Lather the exposed area repeatedly with soap and rinse with warm running water to ease the irritation. If the pain continues, contact your child's physician.

Examples of plants that contain oxalates include:

  • Caladium
  • Calla Lily
  • Devil's Ivy
  • Dieffenbachia (Dumb Cane)
  • Elephant's Ear
  • Jack-in-the-Pulpit
  • Mother-in-Law's Tongue
  • Philodendron
  • Rhubarb
  • Spathiphyllum (Peace Lily)

Gastrointestinal irritants

The juices, leaves, roots and seeds of plants containing gastrointestinal irritants can produce stomach cramps, nausea, vomiting and diarrhea. With most of these plants, vomiting and diarrhea are mild and should last only a few hours. Ingesting small quantities of these plants should not cause any symptoms. However, eating an amount comparable to the size of a small salad would be poisonous.

If your child eats one of these plants, wipe out the mouth and offer food or milk. If vomiting or diarrhea occurs, give plenty of clear liquids to prevent dehydration. If the symptoms are severe and/or prolonged, contact your child's physician.

Examples of gastrointestinal irritants include:

  • Aloe
  • Buckeye-Horse Chestnut
  • Carnation
  • Daffodil
  • Eucalyptus
  • Geranium
  • Hyacinth
  • Pokeweed
  • Pyracantha

Skin irritants

Contact with the leaves or sap of skin-irritant plants can cause a condition called dermatitis, characterized by rashes, hives, swelling and itching of the skin. There are several different types of dermatitis.

Poison ivy or poison oak cause allergic dermatitis. The body's allergic response to the plant toxins may not be apparent for several days and may involve the whole body, even the areas that were not exposed to the plant.

Most of the other plants cause chemical dermatitis; this is not an allergic response but a direct effect of the chemical contained in the plant. Symptoms of chemical dermatitis occur within 24 hours of exposure and are generally confined to the area of contact.

After contact with a skin irritant plant, wash the exposed areas thoroughly with soap and water. Use hydrocortisone cream to treat irritation and inflammation of the skin. Antihistamines may alleviate the itching and hives. The majority of allergic and chemical reactions will clear up in 14-21 days. However, if the symptoms persist or worsen, contact your physician for further treatment.

Examples of skin irritants include:

  • Ruby Plant
  • Schefflera
  • Wandering Jew

Poison Ivy, Poison Oak and Poison Sumac

Poison ivy, poison oak and poison sumac are common causes of seasonal, allergic contact dermatitis (rash). As many as seven out of every 10 people has a reaction after an exposure to these plants. This reaction may range from mild, localized redness and itching to severe blisters and swelling over the entire body.


The irritant in all species of poison ivy, poison oak and poison sumac is an oily resin known as toxicodendrol. This oily resin is found in the leaves, stems, roots and berries of all of these plants.

When this resin comes in contact with skin or fingernails, it clings there and becomes tightly bound within minutes. This means that the most important thing to do is to make sure you wash all areas of the body that were exposed to poison ivy, oak or sumac with soap and water immediately. Even a small delay gives the resin all the time it needs to become tightly bound to the skin and cause a reaction.

Make sure to take special care to clean under the fingernails. Otherwise, any oily resin there could spread to the eyes, genitals or other body parts or even to friends and family members. Contrary to popular belief, the fluid in the blisters does not spread the rash. It is the oily plant resin that is the culprit.

The resin can remain active for long periods of time on contaminated clothing, shoes, sports or hunting equipment, camping gear, garden and yard tools and even the family pet. Repeated washing with commercial detergents is recommended as well as repeated baths if the family pet is involved.

Contaminated clothing, in particular, should be laundered separately several times before wearing because recontamination could occur if your child were to wear these clothes before all traces of resin are removed.


Reviewed by: The Poison Control Center
Date: October 2013

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