Substances Unsafe for Cats

Maine Coon smelling a plant.
Several houseplants can be harmful to cats.


Alexandra Jursova/Getty Images

There are many substances around the home that can hurt cats so it is important for cat owners to be aware of what can cause their kitties harm. Keeping harmful substances out of a cat's reach or locked up and checking the label before feeding something to your cat can help decrease the likelihood of your cat ingesting these items.

Why Are Some Substances Harmful to Cats?

Cats metabolize many things differently than humans and dogs so this means their bodies may absorb things in a way that can cause them harm. Sometimes serious complications such as heart, kidney, or liver failure occur when a cat ingests or is exposed to an unsafe substance but other times it simply causes GI upset such as vomiting and diarrhea. Regardless of the severity of symptoms though, it is best to avoid items that can cause discomfort as well as toxicity to a cat.

Other substances may not be intended to be consumed by a cat and can cause issues like obstructions and foreign bodies in cats. Small toys, holiday decorations, and household items that are small enough for a cat to swallow can cause serious issues even though they aren't toxic.

What Substances are Unsafe for Cats?

  • Alpha Lipoic Acid - This ingredient is used as an antioxidant in some dog and human products but is toxic to cats. Even a small amount can be fatal if a cat eats it.
  • Caffeine - Large amounts of caffiene can cause serious issues in a cat. Problems don't usually occur from a cat simply licking your coffee but if it eats ground coffee or caffeine pills meant for humans it can cause problems with internal organs and the nervous system.
  • Alcohol - Cats should never consume alcohol.
  • Chocolate - Since chocolate contains not only sugar and caffeine but also theobromine, complications with the heart and brain can occur. The darker the chocolate is, the more dangerous it is to your cat and death can occur if enough is consumed.
  • Dairy - Despite popular belief, cats that are no longer nursing do not have the digestive capabilities to break down the proteins and sugars found in dairy products. If an adult cat eats or drinks dairy, diarrhea will occur.
  • Curumin longa - More commonly known as turmeric, some extracts of this plant typically cause vomiting in cats so they are best avoided. They are often found in both dog and human supplements.
  • Medications - There are a number of medications or drugs that can be toxic to a cat. Some medications are safe for cats but human and dog dosages are very different than the dosages that are safe for a cat so you should always consult with your veterinarian before administering anything to your cat. Acetominophen, naproxen sodium, ibuprofen, heart medications, antidepressants, benzodiazepines, and ADD/ADHD medications can be deadly to a cat if ingested.
  • Essential Oils - Wintergreen oil, peppermint oil, citrus oil (including lemon oil), tea tree oil (melaleuca oil), pine oil, eucalyptus oil, cinnamon oil, pennyroyal oil, sweet birch oil, clove oil, ylang ylang oil can all be problematic for cats. Whether inhaled or applied topically, essential oils can be toxic to cats.
  • Grapes and Raisins - It is uknown if grapes and raisins are as concerning for cats as they are dogs but there have been some reports of kidney failure in cats that have eaten them. Because of this, it is better to avoid letting a cat eat these items.
  • Plants - Autumn crocus, amaryllis, azaleas, chrysanthemums, daisies, mums, cyclamen, oleander, daffodils, dieffenbachia (dumb canes), hyacinths, kalanchoe (mother-in-law plants), lilies, lilies of the valley, peace lilies, pothos, devil's ivy, Spanish thyme, marijuana, narcissus, English ivy, mistletoe, poinsettias, yew, castor beans, rhododendrons, sago palms, tulip plants and other plants and herbs can all be unsafe or toxic to a cat. Ingestion of some of these plants or herbs can cause vomiting, diarrhea, heart issues, and even death.
  • Onions, Chives and Garlic - These edible plants can cause major blood problems such as red blood cell rupture in cats and should not be fed.
  • Yeast dough - Raw dough containing yeast can cause issues in a cat if it eats it due to the fermentation of the yeast and expansion of the dough in the stomach.
  • Chemicals - Exposure to antifreeze, bleach, detergents, de-icing salts that cats walk on and then lick their paws, dog flea and tick medication, fertilizers, herbicides, insect and rodent bait and other household chemicals can be toxic to cats and cause a variety of issues including seizures and death.
  • String items - Tinsel, floss, yarn, easter grass and other linear items have been known to be consumed by cats and cause foreign bodies. They can cut through the tongue and intestines and be life-threatening.
  • Other small items - Anything that is small enough to be swallowed, including pieces of toys meant for cats or children, can cause a problem in a cat. Obstructions and foreign bodies can occur and sometimes even cause toxicities depending on what the items are made of.

What Should You Do if Your Cat Ate an Unsafe Substance?

If your cat ate something that is unsafe you should contact a pet poison center. The Pet Poison Helpline at (855) 764-7661 or the ASPCA Animal Poison Control Center at (888) 426-4435 charge a fee for their services but will be able to provide you with detailed information and recommendations on what to do depending on the specific item your cat ate. A veterinary visit may be needed depending on what is recommended.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.