Substances Unsafe for Cats

Common Foods and Other Items That Are Harmful for Feline Friends

Tabby cat drinking in a cup by a window
Linda Raymond / Getty Images

If there is one thing that cats are known for, it is their sense of curiosity. It is not unusual for a kitty to stick its nose where it does not belong. It is important to be aware of foods, items, and substances that you may have in your home that may be potentially dangerous for your cat.

This is by no means a list of everything on the planet that is bad for cats, but this list includes the most common items that should be kept out of reach of your nosy kitty.

Alpha Lipoic Acid

Also referred to as lipoic acid, this antioxidant is a supplement usually taken by people with diabetes or other conditions. If a cat ingests this substance, it can increase production of glutathione, which can cause gastrointestinal distress and low blood sugar.


If your kitty has a few sips of your coffee, tea, or soda, do not worry, it will not contain enough caffeine to cause poisoning in most pets. But, when you really have to worry is if your feline friend ingests moderate amounts of coffee grounds, tea bags, or one to two diet pills, which can easily cause death in cats.


Chocolate contains the alkaloid theobromine which is toxic to cats. It also contains caffeine and may contain sugar. If your cat eats chocolate, it can cause abnormal heart rhythm, tremors, seizures, and death. The darker the chocolate, the more dangerous it is to a cat.


Dairy products like milk, cream, butter, cheese, cottage cheese, yogurt, whey, sour cream, kefir, casein, and ice cream, are not products that are intended for cats. A weaned cat is not equipped with the enzymes needed to digest the protein and sugar in dairy products. Plus, studies with cats show that casein (a protein in milk) interferes with the absorption of other nutrients. Cow's milk is a hormonal growth fluid produced by a mother cow for her young calves. Cats do not "milk" cows and after weaning have no need for dairy products.


There are a number of drugs that are relatively safe for other animals that are very harmful to cats. This list includes aspirin, acetaminophen, antihistamines, decongestants, ibuprofen, NSAIDs, salicylates, and sodium phosphate enemas. Always be certain that any drug you are considering giving your cat is specifically safe for cats. Get advice from your veterinarian before administering anything on your own.

Essential Oils

Cats are very sensitive to the potent essential oils that may be used around you or other animals. If you wish to use aromatherapy for your cats, look into diluted hydrosols. Use caution with cleaning products that contain essential oils. Also, make certain your cat does not get into potpourri.

Grapes and Raisins

There is no doubt that grapes and raisins are toxic to dogs, but there is no clear evidence that grapes and raisins are toxic in cats. There have been some reports of toxic reactions in cats due to grape and raisin ingestion, so until the veterinary community knows more, these are best avoided.


There are many houseplants that are toxic to cats, including azaleas, lilies, and poinsettia. Ingestion of the leaves and berries can cause vomiting, diarrhea, and even death. If you want to give your kitty some green, give it a pot or bed of wheatgrass. In cat circles, it is commonly called "cat grass."


Most common herbs like basil, rosemary, and dill are safe for cats. If you ever gave your kitty some catnip, an herb used for centuries for the treatment of a variety of ailments, you probably have witnessed your cat over the moon with life. But, there are some herbs, particularly herbs that have a strong effect on humans that can negatively impact cats causing a racing heartbeat, vomiting, diarrhea, or even, death. These potentially deadly herbs include foxglove, comfrey, aloe, and castor beans.

Onions and Garlic 

Ingestion of onions and garlic are related to the destruction of red blood cells. They may also irritate the gastrointestinal system. There is still debate about the harmful effects of garlic as many people including holistic vets have used it in cats without a problem, but it is better to be safe than sorry with this potential risk.

Raw Salmon

Salmon poisoning is an infectious disease caused by rickettsia, a type of bacteria that uses a parasitic fluke or worm found on salmon as a host. It can cause serious illness and death. This has no connection with salmonella or salmonellosis, the bacterial infection that can affect dogs and cats. It was also found that an enzyme in raw fish destroys thiamine, which is an essential B vitamin for your cat. A lack of thiamine can cause serious neurological problems and lead to convulsions and coma.


Soy is found in various forms in many products for cats. The carbohydrate action of soy can cause a rise in blood sugar in many cats. Soy is also linked to thyroid damage, and since hyperthyroidism is common in kitties, this is why it should not be part of a feline's diet. Also, it may negatively affect cats by interfering with nutrient absorption, normal growth, and hormonal development.


Much research concludes that cancer cells thrive on sugar as do many other disease processes. Sugar comes in many forms, including beet, raw, brown, cane, fructose, corn sweetener, corn syrup, date, dextrin, dextrose, glucose, lactose, maltose, manitol, polydextrose, sorbital, sorghum, sucanat, sucrose, turbinado, barley malt, molasses, honey, and maple syrup. Xylitol is an artificial sweetener made from sugar alcohol and should be avoided. All alcohol derivatives should be avoided in cats, too.


Yeast is a fungus that many cats cannot tolerate. It may cause allergic reactions, digestive and urinary problems, and bloating. Different forms include brewer's, nutritional, baker's, torula, and primary yeasts.

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.