Plants That are Poisonous to Dogs and Cats

Now that Spring is here many of us will be tending to our gardens, or bringing new plants into our homes. Growing plants in our homes and gardens is good for the environment and can be good for our health and well-being but it is important to remember that some plants are poisonous, and should not be grown anywhere that is accessible to pets and small children.

The extent of poisoning varies depending on the toxicity of the plant and the amount ingested. 

There are hundreds of plants that can cause poisoning in dogs and cats but we couldn't possibly list them all here.  Some of the more common poisonous plants found in South Africa are listed below.

Some common poisonous plants found in South Africa:

Arum lily (Zantedeschia aethiopica)
Elephant's Ear (Alocasia and Colocasia spp.)
Leopard lily/Dumb cane (Dieffenbachia spp.)
Delicious Monster (Monstera deliciosa)


The stems and leaves of these plants contain toxins that cause pain, increased salivation, weight loss and depression. Vomiting and diarrhoea may occur after ingestion of large amounts.

Castor oil plant (Ricinus communis)

The seeds of the castor oil plant are the most poisonous part to dogs and cats but all parts of the plants may result in poisoning when ingested.  Signs of ingestion include vomiting, depression and diarrhoea (which may be bloody).

Clivia lily (Clivia sp.)

The bulbs of the clivia lily are the most poisonous part of the plant and poisoning in dogs and cats can cause vomiting, salivation and diarrhoea. Ingestion of large amounts can cause convulsions, low blood pressure, tremors and irregular heartbeat.

Cotoneaster, firethorn (Cotoneaster spp., Pyracantha spp.)

Ingestion can cause hypoxia, and signs of ingestion include salivation, vomiting and diarrhoea (which may be bloody).

Cycad palms, broodboom (Encephalartos spp., Cycas revoluta, Macrozamia spp., Zamia spp.)

All parts of cycad plants can cause poisoning in dogs and cats, and ingestion can cause vomiting (which may be bloody), diarrhoea, depression, muscle weakness, coma or seizures.

Day lilies, Tiger lilies, Easter lilies (Lilium, Hemerocallis spp.)


The flowers and leaves are poisonous to cats, and ingestion can cause  vomiting, salivation, loss of muscle control, lethargy, tremors, seizures, kidney failure, and death.

English Ivy (Hedera spp.)

Ingestion can cause salivation, vomiting, abdominal pain and diarrhoea.

Honeysuckle (Lonicera spp.)


Clinical signs usually appear within 2 hours after ingestions. These signs include vomiting, diarrhoea, depression and lethargy.

Laburnum (Laburnum spp.)

Ingestion of the pods, leaves and flowers can cause poisoning, which can result in liver damage. Signs of ingestion may include vomiting, diarrhoea (which may be bloody), depression, and in severe cases muscle weakness and seizures.

Macadamia Nuts (Macadamia integrifolia, M. tetraphylla)

Dogs have been known to eat macadamia nuts or kernels with resulting toxic effects. The dose required to induce toxicity in dogs is believed to be between 5 and 40 kernels. Clinical signs usually appear within 12 to 24 hours after ingestion. These signs may include muscle weakness, stiffness and tremors, swelling and pain in hind limbs, depression and vomiting.

Nightshade, Yesterday, today and tomorrow  (Solanum spp. Brunfelsia spp.)


Nightshade fruits, which resemble berries, are most poisonous when green and ingestion can cause vomiting and diarrhoea.

All parts of the yesterday, today and tomorrow plant are poisonous to dogs and cats, and clinical signs appear rapidly after ingestion. Ingestion can cause salivation, vomiting, diarrhoea (often bloody and foul-smelling), frequent urination, loss of muscle control, anxiety and seizures.

Oleander (Nerium oleander)

All parts of the oleander plant are poisonous to dogs and cats, and ingestion can cause diarrhoea (which may be bloody), sweating, lack of coordination, difficulty breathing, muscle tremors, lethargy, and heart failure.

Onions, garlic

Ingestion of onion and garlic can lead to haemolytic anaemia (destruction of red blood cells) in dogs and cats, and can cause vomiting, diarrhoea, abdominal pains and other symptoms.

Panther cap (Amanita pantherina)

This mushroom grows at the base of large trees and ingestion can be fatal. The clinical signs of ingestion include vomiting, diarrhoea, muscle twitching and spasms.

Poinsettia (Euphorbia pulcherrima)

The stems of the poinsettia plant contain a substance that acts as an irritant, causing irritation to the skin, mucous membranes, and digestive tract.

Rhododendrons, azaleas

Poisoning from azaleas usually causes vomiting, and may affect the heart, nervous system, respiratory system and digestive system.

Star of Bethlehem (Ornithogalum spp.)

Ingestion of the bulbs or flowers, or the water in which flowers have been standing, can cause poisoning in dogs and cats. Signs of ingestion include vomiting, diarrhoea, salivation, increased body temperature and lethargy. Severe cases of poisoning can cause loss of muscle control, dehydration and reduced heart functioning, and can be fatal.

Syringa berry tree (Melia azedarach)

Syringa berries are readily eaten by dogs and ingestion can cause restlessness, muscle trembling and weakness, convulsions, difficulty breathing, vomiting and diarrhoea.

Thorn apple, moonflower, olieboom (Datura stramonium)

Ingestion of this plant has been known to cause poisoning in some animals. The effects of poisoning may include agitation, aggression, increased heart rate, rapid breathing, dilated pupils and seizures.

If you suspect that your pet has ingested a poisonous plant, take them to the vet straight away. Most cases of plant ingestion by dogs and cats result in mild poisoning, however some cases can result in severe effects such as organ damage or death. 


Cathy Dittrich
Cathy Dittrich