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Nematology (Botany) Circular No. 35 Fla. Dept. o Agric. & Consumer Serv.
January 1978 Di vision 9AV "Tstry
DUMBCANE DIEFFENBACHIAA SP.) University of Florida
A COMMON POISONOUS ORNAMENTAL PLA-
K. R. Langdon
Several different species and many cultivars of Dieffenbachia, including
D. picta (Lodd.) Schott (fig. 1), are grown as ornamentals, primarily as pot
plants, or in south Florida and the tropics, outdoors as well. The plants pro-
duce attractive, large, variegated or variously mottled foliage, useful for a
Fig. 1. Dieffenbachia picta (after West, 1960)
Contribution No. 177, Bureau of Nematology, P.O. Box 1269, Gainesville, FL 32602
The genus Dieffenbachia is a member of the Araceae family and produces
many tiny flowers on a spike or spadix enclosed in a spathe, as do other mem-
bers of the family. This entire inflorescence is often mistaken for a single
flower, but is actually an aggregate of many flowers.
he various species of Dieffenbachia may grow to as much as 6 ft. (1.8 m)
tall with 'tiEk, fleshy, usually green stems usually 1 in. or less thick, but
sometimes" up^'tc around 2 in. (50 mm) thick. The leaves have short or long
petioles clasping the stem at the base. The blades are up to 6 in. (15 cm)
wide and as much as 14 in. (35 cm) long, tapering, rounded, or subcordate at
the base and acute to acuminate at the tip. The leaves are green or variously
marked or spotted with white or cream. All parts of the plant are smooth (gla-
All parts of the plant, especially the stem, contain a slightly milky sap
and needle-like crystals of calcium oxalate. This sap is extremely irritating,
especially if a piece of the plant is chewed or swallowed. It can also be ir-
ritating to the hands, etc., as a result of cutting or handling pieces of the
plant. The exact cause of the irritation is a subject of controversy. Some
people consider the calcium oxalate crystals to be the primary irritants, but
there is evidence to indicate that some other chemicals, as yet unidentified
but possibly protoanemonine, causes most of the irritation.
Biting, chewing, or tasting this plant quickly produces irritation and
burning of the mouth, tongue, and lips, copious salivation, and swelling of the
tongue and throat which may make the tongue immobile and speech impossible
(hence the name "dumbcane"). This may interfere with swallowing and breathing,
and may last for up to several days to a week or more. Severe cases require
immediate medical attention to prevent asphyxiation from impaired breathing.
Mild poisoning cases usually recover fully without treatment; however, more se-
vere cases require medical treatment and can prove fatal. At least 3 deaths
from dumbcane poisoning have been reported from Brazil. In another report a
man attempted suicide in a bar by eating a portion of D. picta. He vomited,
became red in the face, experienced swelling of the mouth and tongue, collapsed,
and remained unconscious for 36 hours. He was revived and given medical treat-
ment, but could not retain solid food because of the caustic action on his
stomach from which he finally recovered in 2 1/2 months.
There are records of the use of Dieffenbachiaby South American Indians as
arrow poison. It has been reported to produce temporary sterility and has been
used by these Indians to sterilize their enemies. Other reports indicate its
use during World War II in sterility experiments on concentration camp inmates.
In colonial days it was used for punishing slaves in Jamaica by rendering them
Small children are especially vulnerable to poisoning by Dieffenbachia be-
cause of their tendency to chew or taste almost anything. Considerable pre-
cautions should be taken where small children are involved to keep these plants
out of their reach and to insure that they are not poisoned.
Kingsbury, J. M. 1964. Poisonous plants of the United States and Canada.
Prentice-Hall, Englewood Cliffs, N. J. 626p.
Morton, Julia F. 1971. Plants poisonous to people. Hurricane House, Miami.
Oakes, A. J. 1962. Poisonous and injurious plants of the U. S. Virgin Islands.
ARS, USDA Miscellaneous Publication No. 882. 97p.
West, E. 1960. Poisonous plants around the home. Fla. Agric. Ext. Serv. Bull.