Pisang Tanah, Dumb Cane

Seen this picture in your email? It came with a warning from a Dr Kivumby that it could “kill” a child in less than a minute and an adult in 15 minutes.

Each one of us here has received this email from our well-meaning friends. So please allow us to try to put this plant in better perspective.

This is Dieffenbachia, also called ‘dumbcane’ in English and ‘kotakimbula’ in Sri Lanka. At home it is known as ‘pisang tanah’ because of it thick succulent stem.

Dieffenbachia is a common ornamental plant. Plants are all around us. We use them to enhance the beauty of our surroundings. Almost every herb, vegetable and fruit has medicinal properties. Plant extracts are widely used in cosmetics. Despite their varied uses, some plants are also a potential source of poisoning to curious young children and pets.

The Indiana Poison Center classified this plant as having the potential to be mildly toxic with symptoms which are generally not life-threatening in nature, such as nausea, vomiting, diarrhea, or skin rashes.

The latest update from the Medline Plus, a service of the US National library of Medicine and National Institutes of Health, recognizes oxalic acid and asparagine as the poisonous ingredients in this plant.

Interestingly, oxalic acid is also found in starfruit and spinach while asparagine, an amino acid, is found in potatoes, soya bean and asparagus and is listed as an existing food additive in Japan. Poisoning from Dieffenbachia probably results the combined actions of oxalic and asparagines.

However, Bernard Kuballa et al¹ reported that its irritative nature could be due to the combination of the oxalate crystals and a trypsin-like enzyme. It is believed that the needle-shaped crystals penetrate the soft tissues of the throat and mouth making it easier for the entry of the proteolytic enzyme.

Oral contact with the plant usually is associated with minimal consequences. However, in rare cases, chewing on the stem or the leaf of the Dieffenbachia can cause swelling severe enough to block the airways and affect the ability to speak or handle secretions (thus its dumbcane moniker).

Most cases of poisonings involve pets.² Kirk L Cumpston et al³ reported a case of an adult who bit into the stem of the plant thinking it was sugar cane. He instantly spat out the remaining stem and despite this brief exposure, oral airway swelling developed which did not respond to medicinal therapy, thus requiring surgical airway management. The authors confessed to not knowing the exact mechanism of the oedema but cautioned that a patient who initially seems stable may have an airway that will quickly deteriorate.

If you have an exposure, you should call your local emergency number or our National Poison Control Center at 1-800-88-8099.

House plants can be very beneficial in our homes and lives. House plants can not only purify and renew our stale indoor air, by exchanging the carbon dioxide we exhale with life sustaining oxygen, but they can also trap many of the pollutants present in our homes and offices.

You can choose not to have Dieffenbachia at home. But, please don’t simply throw away your in-door and garden plants.

Follow these tips to reduce the risk of poisoning from plants in your home:

• Keep all plants up off the floor and out of reach of children and pets.
• Think about using fake instead of real flowers and plants if young children or pets live in or visit your home.
• Store bulbs and seeds locked away, out of sight and reach of children.
• Never eat any part of an unknown plant.
• Teach children to show all plants and berries to an adult before eating.
• Never chew on jewelry, etc., made from plant material or allow children to do so.
• Don’t rely on cooking to destroy poisons in plants.
• Remember that plants can also be a choking danger for children and pets.

Journal Reference:

Kuballa B, Lugnier AA, Anton R. Study of Dieffenbachia-induced edma in mouse and rat hindpaw: respective role of oxalate needles an trypsin-like protease. Toxicol Appl Pharmacol. 1981 May;58(3):444-51.

Peterson K, Beymer J, Rudloff E, O'Brien M. Airway obstruction in a dog after Dieffenbachia ingestion. J Vet Emerg Crit Care (San Antonio). 2009 Dec;19(6):635-9.

Cumpston KL, Vogel SN, Leikin JB, Erickson TB. Acute airway compromise after brief exposure to a Dieffenbachia plant. J Emerg Med. 2003 Nov;25(4):391-7.