Toxic foods for cats: lilies, onions and other dangers

Lilies and the onion family are two of the most dangerous household hazards for cats, and both can kill. Lilies damage a cat's kidneys but not a dog's, and cats are more sensitive than any other species to onion and garlic. Many other foods on the usual danger lists are risky for cats too, though a few are less dangerous than often claimed, and some of the evidence comes only from dogs.

Emergencies that need a vet the same day

Lilies

Lilies are not a food, but they belong at the top of any list for cats. Every part of a true lily (Lilium) or daylily (Hemerocallis) is toxic: stem, leaves, flowers, pollen and the water in the vase. Chewing a small piece of leaf or petal, licking a few pollen grains off the coat or drinking vase water can cause fatal kidney failure in less than three days, according to the FDA's guidance on lilies and cats. The toxin itself has not been identified.

The first signs are vague: less activity, drooling, vomiting and loss of appetite, starting within 12 hours. Kidney damage follows, and kidney failure develops within 24 to 72 hours. Timing decides the outcome. If treatment is delayed 18 hours or more after exposure, the kidney failure is generally irreversible, so a cat seen near a lily should go to the vet before any signs appear.

Easter, Asiatic, tiger, Oriental, stargazer and wood lilies and daylilies are among the dangerous ones. Peruvian lilies, despite the name, do not cause kidney failure. Households with cats are safest with no true lilies or daylilies indoors at all, including in cut bouquets.

Onions, garlic, chives and leeks

These plants damage red blood cells and cause hemolytic anemia. Cats are the most susceptible species. The Merck Veterinary Manual notes poisoning in cats after less than a teaspoon of cooked onion or 5 g/kg of raw onion, and garlic is three to five times more toxic than onion. Concentrated forms are the usual culprits: onion or garlic powder, dehydrated flakes and dry soup mixes. Gravies, stocks and some baby foods can contain them.

Signs usually appear several days after eating, which makes the link easy to miss. Watch for weakness, pale or yellow gums, fast breathing, dark urine and collapse. Report any onion or garlic exposure to the vet even if the cat seems well.

Chocolate, coffee and caffeine

Chocolate, coffee and caffeine contain methylxanthines, which can cause vomiting, diarrhea, restlessness, abnormal heart rhythm, tremors, seizures and death. Darker chocolate carries more risk: baking chocolate and cocoa powder have the highest concentrations and white chocolate the lowest. Cats rarely go looking for chocolate, which fits the finding that a gene deletion leaves them indifferent to sugar and probably unable to taste it. Coffee grounds, tea bags and caffeine tablets are still worth keeping out of reach.

Foods that call for a phone call to the vet

Alcohol and raw yeast dough

Alcohol is absorbed quickly and can cause vomiting, incoordination, breathing difficulty, tremors, changes in blood pH, coma and death. Cats are small, so the amount that matters is small. Foods count too: rum cakes, wine sauces and fermenting fruit.

Raw bread or pizza dough keeps rising in the warm stomach. It can bloat the stomach painfully, and the yeast produces alcohol as it ferments, so a cat can develop alcohol poisoning from dough alone.

Grapes and raisins

Grape and raisin poisoning is documented mainly in dogs, where it causes kidney damage. Tartaric acid is the suspected toxin, according to the ASPCA Animal Poison Control Center. Whether cats are affected in the same way is not well established. Because the dog cases can be severe, treat a cat that has eaten grapes or raisins as a possible poisoning and ask the vet.

Xylitol

Xylitol, the sweetener in sugar-free gum, mints, some baked goods and toothpaste, causes dangerous low blood sugar and liver damage in dogs. The picture in cats looks different. In a small study, cats given xylitol at doses that are toxic to dogs showed no significant changes in liver enzymes or other blood values, and their blood glucose did not drop. Six cats is a small sample, so products containing xylitol should still be stored away, but a cat that licks a sugar-free sweet is not in the same danger as a dog.

Foods that cause illness or deficiency

Milk and dairy

Kittens digest their mother's milk, but many adult cats are lactose-intolerant and get diarrhea or other digestive upset from cow's milk. Cornell's Feline Health Center does not recommend milk as a treat, and notes that dairy products can cause digestive problems in lactose-intolerant cats.

Raw meat, fish and eggs

Raw meat and raw eggs can carry Salmonella and E. coli, which can infect both the cat and the people in the house. Raw meat can also carry toxoplasmosis. Raw egg white contains avidin, which interferes with the absorption of biotin, and long-term feeding can cause skin and coat problems. Cooked egg does not have this effect.

Some raw fish contain thiaminase, an enzyme that breaks down thiamine (vitamin B1). Thiamine deficiency in cats causes neurological signs such as loss of balance and seizures. Fish canned for people is not a complete diet either, and Cornell notes that some cats fed canned fish meant for humans have developed serious neurological disorders.

Dog food

A mouthful of the dog's dinner does no harm, but dog food is formulated for dogs and is not made to meet a cat's needs. Cats are obligate carnivores and need certain nutrients from their diet, taurine among them. In the 1980s low taurine was linked to a form of heart muscle failure in cats that improved with taurine supplements. A cat that regularly eats from the dog's bowl needs its feeding arrangements changed.

Bones

Cooked bones, especially poultry bones, splinter. Any bone can injure the mouth or block or damage the gut, and some of those injuries need surgery. Signs to watch after a cat eats a bone include retching, drooling, straining, vomiting and refusing food.

Other foods to keep off the plate

• Citrus: the peel, leaves and seeds contain essential oils that can irritate the stomach. A lick of the fruit usually causes no more than mild upset.
• Coconut and coconut oil: small amounts are unlikely to cause serious harm, but the oils can cause loose stools and diarrhea.
• Nuts: almonds, pecans and walnuts are high in fat and can cause vomiting, diarrhea and possibly pancreatitis. Macadamia poisoning is described in dogs.
• Wild mushrooms: some species are deadly, and a cat cannot tell them apart. Plain store-bought mushrooms are a lower concern.

If a cat eats something toxic

Note what was eaten, how much and when, then call the vet or an animal poison control line straight away. The ASPCA Animal Poison Control Center is reachable on (888) 426-4435. Do not wait for signs, and do not try to make a cat vomit at home. Bring the packaging, or for plants a photo or piece of the plant, so the vet can identify it. Because cats groom, anything on the coat, such as pollen or spilled food, should be gently washed off to stop further swallowing.

Sources

1. Lovely lilies and curious cats: a dangerous combination. U.S. Food and Drug Administration.
2. Garlic and onion (Allium spp) toxicosis in animals. Merck Veterinary Manual.
3. People foods to avoid feeding your pets. ASPCA Animal Poison Control Center.
4. Pseudogenization of a sweet-receptor gene accounts for cats' indifference toward sugar. PLoS Genetics, 2005.
5. Effects of p.o. administered xylitol in cats. Journal of Veterinary Pharmacology and Therapeutics, 2018.
6. Feeding your cat. Cornell Feline Health Center.
7. Myocardial failure in cats associated with low plasma taurine: a reversible cardiomyopathy. Science, 1987.