It's understandable wanting to share a snack with your cat—but before you do, it's important to know what foods are toxic for cats, since many popular human foods are poisonous to our feline friends.

Cats are full-fledged members of the family, and as such, it often seems only natural to share everything with them—including meals. But depending on the food, sharing your plate can harm your cat's health. Before you share that snack, be sure to know the difference between foods that are toxic to cats and the ones that are safe.

Should You Feed a Cat Human Food?

It's important to note that despite your cat's whining, treats and snacks suited for people just aren't an essential part of his diet. We teamed up with the University of Missouri Small Animal Clinical Nutrition Service in Columbia, Mo., to find out what your cat needs to eat to be healthy. As it turns out, not much (outside of their regular cat food, that is).

man feeding cat a piece of candy
Credit: Chalabala / Getty

"Cats have specific nutrient requirements that must be met by their diet," the Clinical Nutrition Service says. "The simplest and most convenient way to meet a cat's nutrient requirements is to provide them with a complete and balanced commercial diet formulated by a board-certified veterinary nutritionist or an individual with a PhD in animal nutrition." 

This means that any vitamins and minerals provided by treats—even things like fruits and vegetables that us humans would consider healthy snacks—would exceed what a cat eating a complete and balanced diet needs. And when it comes to nutrients, more isn't always merrier. In some cases, it can even be harmful. 

What Kinds of Human Foods are Safe for Cats to Eat?

But if you still want to treat your cat, the Clinical Nutrition Service says there are several human foods that are generally considered to be safe for cats, as long as they don't account for more than 10 percent of a cat's daily intake. "For example," the Clinical Nutrition Service explains, "if a cat is consuming 250 calories per day, no more than 25 of those calories should come from any unbalanced food sources." 

However, the Clinical Nutrition Service also cautions that cats must be considered for their individual needs, since some cats may consume a particular food item with no issue and another cat may consume the same item and develop vomiting, diarrhea, or other adverse signs. With this in mind, it's always a good idea to talk to your veterinarian before adding any new human foods to your pet's diet—even ones that are typically considered to be safe. 

Which Human Foods are Toxic to Cats?

"There are human foods that are dangerous and should never be fed to cats," the Clinical Nutrition Service says. The ASPCA has a lengthy list of human foods to avoid feeding your cat, but it's probably not an exhaustive list since many food items have not undergone peer-reviewed studies that have determined how toxic they are.

Here are a few no-gos from the ASPCA's list of human foods that cats should avoid:

  1. Alcohol. Drinks and foods containing alcohol can cause serious problems in pets, including vomiting, diarrhea, breathing difficulties, coma, and death.
  2. Bread dough containing yeast. Yeast dough can rise and cause gas to build up in your cat's digestive system. This can lead to stomach bloating and even twisting, which is a potentially fatal condition. Moreover, yeast produces alcohol as a byproduct, which has its own set of problems (see above). Baked bread, however, is considered safe for healthy cats.
  3. Chocolate. Chocolate contains substances called methylxanthines (specifically, theobromine and caffeine) that are toxic to pets and can cause vomiting, diarrhea, tremors, seizures, and death. The concentration of methylxanthines varies among different types of chocolate. Cocoa powder is the most dangerous, while white chocolate is the least. 
  4. Coffee. Like chocolate, coffee contains the methylxanthine caffeine and can thus have the same effects listed above. 
  5. Citrus fruits. Citrus fruits like lemons, limes, oranges, clementines, and grapefruits contain citric acid and essential oils that can cause problems in cats. The stems, leaves, peels, fruit, and seeds should all be avoided. While small amounts will likely cause only an upset stomach, large amounts can lead to diarrhea, vomiting, and central nervous system depression.
  6. Coconut flesh and coconut water. Fresh coconut milk and flesh can cause digestive issues in pets, though small amounts aren't likely to cause serious harm. Coconut water is too high in potassium to be safe for pets, though coconut oil might be helpful for some cat skin issues. Talk to your vet before using this as a holistic remedy or including it in your cat's diet. 
  7. Dairy. Feeding your cat dairy products can cause digestive problems, since many cats are lactose intolerant and can't process dairy (milk, cheese, yogurt) appropriately. The safest approach is to avoid them altogether, but you can ask your vet if a lactose-free alternative is an acceptable treat.
  8. Grapes and raisins. While the exact reason why these are poisonous to pets remains unknown, there's evidence that feeding cats (and dogs!) grapes and raisins can lead to kidney failure
  9. Nuts. Macadamia nuts are toxic to pets, and like grapes, the exact mechanism of toxicity is unknown. Other types of nuts, including almonds, pecans, and walnuts, are rich in oils and fats that can cause digestive upset and potentially even pancreatitis in cats
  10. Raw eggs. Raw eggs may be contaminated with Salmonella bacteria. Signs of infection include vomiting, diarrhea, and fever. Raw eggs also contain avidin, an enzyme that hinders cats from absorbing biotin, a vitamin that's important for skin and fur health.
  11. Raw or undercooked meat. Similar to raw eggs, raw or undercooked meat can be contaminated with Salmonella and E. coli bacteria. The Clinical Nutrition Service says that it often sees gastrointestinal signs (typically diarrhea) in pets consuming raw meat-based diets. 
  12. Raw fish. Like raw meat and eggs, raw fish can carry bacteria that cause food poisoning.
  13. Salt. In large amounts, salt and salty foods can cause vomiting, diarrhea, tremors, seizures, and death in pets. 
  14. Some vegetables and herbs. Though cats can eat some vegetables, onions, garlic, leeks, scallions, shallots, and chives are particularly harmful to cats, causing gastrointestinal problems and even damage to red blood cells. Foods containing these vegetables and herbs, such as garlic bread, should be avoided, as well. 
  15. Xylitol. Xylitol is a common sweetener in packaged goods like gum and candy that can lead to vomiting, lethargy, and liver failure in pets. 

What Should You Do if Your Cat Eats Something Toxic?

If you know or suspect that your cat has eaten a food item from the toxic list, call your veterinarian or the ASPCA Animal Poison Control Center at 888-426-4435 as soon as possible. You don't need to wait until your cat shows any signs of illness to seek help. The sooner you address any problems or potential problems, the better.

Thankfully, the Clinical Nutrition Service says that it rarely sees cats with food-related toxicosis. It's typically more of a problem with dogs, who are more adventurous and undiscriminating with regards to what they eat. And just like your cat, who is more than likely apprehensive about trying new foods, it also pays for you to be picky in what you feed them. Before making any changes to your cat's diet, talk to your veterinarian about which ingredients are safe, and what amounts are OK for your cat to try. No question (or treat) is too small for you to discuss.