Hundreds of plants exist that are toxic to cats, but many of these are not typically kept as houseplants. Those that are have varying degrees of toxicity, and may or may not do serious harm to your cat if she nibbles on them. To be as safe as possible, avoid bringing potentially harmful plants into your home. If you suspect that your cat has nibbled on a potentially toxic plant, take the cat and the plant to the veterinarian immediately. Also take her if she is showing signs of poisoning even if you aren't sure that she's eaten a harmful plant.
Aloe vera is a common houseplant that is kept for its soothing, healing properties the juice has for small kitchen burns or sunburn. While the relatively hard, sharp leaves are not particularly inviting to cats, if your cat takes a bite he can become very ill. Symptoms include discolored urine, diarrhea, tremors, vomiting, anorexia and depression.
American holly, also known as winterberry, English holly, Oregon holly, European holly and inkberry, goes by the scientific name Ilex opaca. While not highly toxic, both the leaves and the bright red berries can make your cat sick if she ingests them. Symptoms include diarrhea, depression and vomiting.
Begonias typically have attractive leaves and flowers that come in many different colors. With thousands of different varieties of this plant, begonias find their way into many homes. A cat that ingests any part of this plant can experience vomiting, excessive drooling, extreme irritation of lips, tongue and mouth and burning and trouble swallowing. The tubers are the most toxic part of this plant.
True members of the lily family, such as day, tiger, Asiatic, Japanese show and Easter lilies, are all very toxic to cats. These types of lilies can cause kidney failure, and a cat that eats any part of one needs immediate aggressive treatment if he is to survive. Other types of lilies, including cala and peace lilies, cause milder symptoms such as mouth and throat irritation that shows up as drooling.
Azaleas may be planted outdoors or kept as house plants, but either way they are highly poisonous to cats. Eating the leaves will result in extreme drooling, diarrhea and vomiting, and if the cat doesn't get treatment she can go into a coma and potentially die.
Dieffenbachia plants are a popular type of greenery kept in many homes, but they should be kept away from pets. A cat that ingests this plant will end up drooling from severe mouth irritation, experience vomiting and nausea and have difficulty swallowing.
Other Problem Houseplants
Many other kinds of houseplants can cause your cat to become ill, with symptoms that may include drooling, vomiting, diarrhea, lethargy, difficulty walking and depression. Such plants include lily of the valley, sago palm, amaryllis, autumn crocus, chrysanthemum, English ivy, cyclamen, pothos, Spanish thyme, tulips, castor beans, asparagus fern, bleeding heart, Christmas rose, clematis, elephant ear, evergreen ferns, philodendron, schefflera, rubber plant and tomato plants.