Merck Manual

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Poisonous Houseplants and Ornamentals

Poisonous Houseplants and Ornamentals

Common Name

Scientific Name (Family)

Toxic Parts and Effects

Treatment

Autumn crocus, Crocus, Fall crocus, Meadow saffron, Wonder bulb

Colchicum autumnale (Liliaceae, Colchicaceae)

Entire plant is toxic. Milk of lactating animals is a major excretory pathway. Observed signs are thirst, difficult swallowing, abdominal pain, profuse vomiting and diarrhea, weakness, and shock within hours of ingestion. Death from respiratory failure.

Prolonged course due to slow excretion of the toxin. Flush out stomach contents; supportive care for dehydration and electrolyte losses (fluid therapy); central nervous system, circulatory, and respiratory disturbances. Analgesics and atropine recommended for abdominal pain and diarrhea.

Avocado pear, Alligator pear

Persea americana (Lauraceae)

All above-ground parts (leaves in particular) reported toxic to cattle, horses, goats, rabbits, canaries, ostriches, and fish. Toxicity associated with loss of milk production (cattle, rabbits, goats), lung congestion, irregular heart beat, swelling of the jaw, sudden death (rabbits, caged birds, goats), respiratory distress, generalized congestion, subcutaneous swelling, and fluid around the heart (suggestive of cardiac failure, caged birds). In caged birds, signs may be seen within 24 hours (usually after 12 or more hours), with death 1 to 2 days after exposure.

Primarily symptomatic and supportive (See also Food Hazards : Avocado)

Azalea, Rhododendron

Rhododendron species (Ericaceae)

Entire plant, including pollen and nectar. Within hours of ingestion of toxic dose (1 gram/kilogram), drooling, tearing, vomiting, diarrhea, difficulty breathing, muscle weakness, convulsions, coma, and death. Signs may last several days, but toxin is not cumulative.

Supportive; flush out stomach contents, activated charcoal, saline cathartics, calcium injection, and antibiotics to control possible pneumonia suggested.

Barbados aloe, Curacao aloe

Aloe Barbadensis (Liliaceae)

Latex of the leaves; higher concentrations in younger leaves. Upon eating, causes abrupt, severe diarrhea and/or low blood sugar, with vomiting in some cases.

Supportive; control diarrhea and fluid loss.

Caladium, Fancy leaf caladium, Angel wings

Caladium species (Araceae)

Entire plant is toxic. Ingestion causes immediate intense pain, irritation to mucous membranes, excess drooling, swollen tongue and pharynx, diarrhea, and difficulty breathing. Pets’ access to plant associated with rhizomes brought indoors for winter storage.

Supportive

Century plant, American aloe

Agave americana (Agavaceae)

Leaves, seeds, and sap. Upon eating, causes skin and mouth irritation and swelling.

Supportive

Cherry pepper, Chili pepper, Ornamental pepper, Capsicum

Capsicum annuum (Solanaceae)

Capsaicinoids (capsaicin) in the mature fruits, solanine and scopoletin in foliage; irritating to the stomach and intestinal tract, with vomiting and diarrhea. Not likely to be lethal.

Supportive; irritation relief—flush with cool water, topical or oral mineral or vegetable oil. Rarely topical anesthetics.

Chinese evergreen, Painted drop tongue

Aglaonema modestum (Araceae)

Entire plant. Upon eating, causes mouth irritation and swelling.

Supportive

Coontie, Florida arrowroot, Seminole bread, Cycad

Zamia pumila (Zamiaceae)

Leaves, seeds, and stem. Ingestion associated with liver and stomach and intestinal disturbances and incoordination. Signs are persistent vomiting, diarrhea, abdominal pain, depression, and muscular paralysis.

No specific therapy; intravenous fluids and supportive care recommended.

Cyclamen, Snowbread, Shooting star

Cyclamen species (Primulaceae)

Tuberous rhizomes cause stomach and intestine irritation, thereby increasing absorption and severe toxicity. Reduced appetite, diarrhea, convulsions, and paralysis can occur. Pets have greater access to these plants over winter months (both pets and plants are indoors).

Supportive

Daffodils

Narcissus species (Amaryllidaceae)

Same as for hyacinths (see below).

Same as for hyacinths (see below).

Dragon tree

Dracaena species (Agavaceae)

Leaves. Vomiting and severe diarrhea indicative of stomach and intestinal irritation expected. No cases have been reported.

Supportive, to correct fluid and electrolyte (salt) imbalance.

Dumbcane

Dieffenbachia species (Araceae)

Entire plant, including sap. On ingestion, immediate intense pain, burning, and inflammation of mouth and throat, no appetite, vomiting, and possibly diarrhea, with tongue extended, head shaking, excessive drooling, and difficulty breathing. Immediate pain limits amount consumed. Death infrequent.

Supportive

Easter lily, Trumpet lily

Lilium longiflorum; L. tigrinum (Liliaceae)

Entire plant is toxic. Kidney system failure in cats 2 to 4 days post-ingestion. Not reported toxic to other species. Vomiting, depression, loss of appetite within 12 hours post-ingestion.

Emetics (induce vomiting), activated charcoal, saline cathartic, and nursing care—as for renal failure—within hours of ingestion. Delayed treatment is associated with poor prognosis.

English holly, European holly

Ilex aquifolium (Aquifoliaceae)

Leaves, fruits, and seeds. Abdominal pain, vomiting, and diarrhea seen after ingestion of 2 or more berries. Death is rare.

Supportive (at best)

Foxglove

Digitalis purpurea (Scrophulariacae)

Entire plant is toxic. Generally, sudden abdominal pain, vomiting, bloody diarrhea, frequent urination, irregular slow pulse, tremors, convulsions, and rarely death.

Supportive

Hyacinths

Hyacinthus species (Liliaceae)

Bulbs. After ingestion of toxic dose (bulbs), vomiting, diarrhea, and rare deaths reported. Bulbs in storage may be accessible to pets.

Supportive

Jerusalem cherry

Solanum pseudocapsicum (Solanaceae)

Leaves and fruits. Loss of appetite, abdominal pain, vomiting, diarrhea with blood, drooling, progressive weakness or paralysis, difficulty breathing, irregular heartbeat, circulatory collapse, dilated pupils, and convulsions reported.

Supportive; flush out stomach contents, activated charcoal, electrolytes and fluids, and anticonvulsants suggested.

Kalanchoe, Air-plant, Cathedral-bells

Kalanchoe species (Crassulaceae)

Leaves. Within hours of ingesting toxic dose, depression, rapid breathing, teeth grinding, lack of coordination, paralysis, muscle spasms (rabbit), and death (rat).

Supportive; atropine has been effective in rabbits.

Lily-of-the-valley, Conval lily, Mayflower

Convallaria majalis (Liliaceae)

Leaves, flowers, rhizome, and water in which flowers have been kept. Variable period before signs arise depending on dose. Stomach and intestinal signs (vomiting, trembling, abdominal pain, diarrhea), progressive heart irregularities, and death. High blood pressure in sudden cases. Inflammation of the stomach and intestine, bleeding of small capillaries throughout.

Aimed at gut decontamination (flushing of stomach contents) and at correcting irregular heart beats and electrolyte (salt) imbalances. Monitoring of EKG and serum potassium necessary.

Marijuana, Mary Jane, Grass, Pot, Hashish, Indian hemp, Reefer, Weed

Cannabis sativa (Cannabaceae)

Leaves, stems, and flower buds of mature plants or edible products intended for people that contain tetrahydrocannabinol (THC). Lethal dose for dogs is more than 3 grams/kilogram body weight. Pets’ exposure usually from accidental access to this plant being used for medical or recreational uses by owner. Pets (dogs primarily) show incoordination, vomiting, dilated pupils, prolonged depression, excessive or irregular heartbeats, drooling, hyperexcitability, tremors, and fever. Death results when vital central nervous system regulatory centers are severely depressed.

Remove animal from source. Effectiveness of emetics limited by antiemetic effect of THC (the toxic compound in the plant). Oral tannic acid, activated charcoal followed by saline cathartics have been recommended. Stimulants (cardiac and respiratory) along with supportive therapy essential in severely depressed animals. Recovery slow at best (See also Poisonings from Illicit and Abused Drugs : Marijuana).

Mistletoe

Phoradendron flavescens (Viscaceae)

Entire plant is toxic. Vomiting, profuse diarrhea, dilated pupils, rapid labored breathing, shock, and death from cardiovascular collapse within hours of ingesting toxic dose.

Supportive

Philodendron

Philodendron species (Araceae)

Entire plant is toxic. On ingestion, immediate pain, local irritation to mucous membranes, excessive drooling, swollen tongue and pharynx, difficulty breathing, and kidney system failure. Excitability, nervous spasms, convulsions, and occasional brain swelling reported in cats.

Supportive

Poinsettia, Christmas flower, Christmas star

Euphorbia pulcherrima (Euphorbiaceae)

Milky sap. Irritates mucous membranes and causes excessive drooling and vomiting but not death.

Supportive; flush out stomach contents, activated charcoal, and saline cathartics should be considered.

Sansevieria, Snake plant, Mother-in-law’s tongue

Sansevieria species (Agavaceae)

Leaves and flowers. Vomiting, drooling, diarrhea, and rupture of red blood cells related to stomach and intestinal activity of these compounds.

Supportive; fluids and electrolytes may be necessary.

Schefflera, Umbrella tree

Schefflera species (Araliaceae)

Leaves. Mucous membrane irritation, drooling, loss of appetite, vomiting, and if severe enough, diarrhea.

Supportive

Spider plant, St. Bernard’s lily, Airplane plant

Chlorophytum species (Liliaceae)

Leaves and plantlets. Vomiting, drooling, retching, and varying degrees of loss of appetite seen in cats within hours of ingestion. Deaths and diarrhea not reported.

Supportive

Yesterday-today-and-tomorrow, Lady-of-the-night

Brunfelsia pauciflora floribunda (Solanaceae)

Flowers, leaves, bark, and roots. Upon eating, animals show abnormal heart rhythms, dry mouth, dilated pupils, difficulty breathing, tremors, depression, urinary retention, and sometimes coma (deep sedation). Not reported to cause death.

In severely depressed animals, stimulants (respiratory and cardiac), along with supportive therapy recommended.

Yew

Taxus species (Taxaceae)

Entire plant except the fleshy aril (red covering of the seeds). Nervousness, trembling, incoordination, difficulty breathing, collapse; slowing of heartbeats progressing to the heart stopping and death without struggle. Empty right side of heart; dark, tarry blood in left side of heart.

Supportive at best; usually futile once signs appear. Atropine may be helpful.