Toxic plants

Is Onion Toxic To Cats?

Is Onion Toxic To Cats? 
Written by Clair Chesterman

If a feline consumes more than one gram per five pounds of body weight, an onion can become toxic. Onion powder is highly toxic and potentially more potent than fresh onions. The toxic component of onions is an oxidant called n-propyl disulfide.

Cats have a high sensitivity to red blood cell oxidation because their cells have a larger surface area for oxidizing agents to attach to. When n-propyl disulfide is digested and enters the bloodstream, it attaches to the red blood cell and cannot be easily removed, the body destroys the cells in an attempt to rid itself of the harmful substance. As a result, the red blood cell will break down; this event is called hemolysis.

What Is An Onion?

Scientifically known as Allium cepa, the onion is a biennial plant that is widely cultivated around the world and commonly used for culinary purposes. Yellowish- to bluish-green leaves grow alternately in a flattened, fan-shaped swath on the onion plant. As it matures, the bulb at the plant’s base begins to swell. The bulbs are made up of shortened, compact underground stems that are surrounded by bulbous scales or leaves that surround the central bud at the stem’s tip.

The onion is most likely native to southwestern Asia, but it is now grown all over the world, primarily in temperate zones. Onions are extremely hardy and can thrive in a variety of growing conditions. The bulbs vary in size, shape, color, and pungency, with warmer climates producing milder, sweeter onions than other climates.

Clinical Signs of Onion Poisoning in Cats

A hypersensitive reaction of the cat’s red blood cells to the oxidant present in fresh or dried onions causes onion poisoning.  Typical indicators of onion poisoning in felines may include the following:

  • Contact dermatitis 
  • Collapse
  • Diarrhea
  • Dyspnea
  • Increased heart rate 
  • Hematuria or blood in the urine
  • Hemolytic anemia
  • Liver damage 
  • Lethargy 
  • Panting 
  • Pale Gums
  • Weakness 
  • Vomiting

First Aid and Treatment of Onion Poisoning in Cats

Onion poisoning has no specific cure, hence the illness is mostly managed with supportive care. The feline may be given intravenous fluid therapy as it is used to flush the poison out of the body and gives the body time to stop hemolyzing red blood cells. In most situations, once the toxin has been removed from the cat’s system, the bone marrow will begin producing new, healthy red blood cells to replace the ones that were damaged. In severe cases of blood loss, a blood transfusion may be required to refill the feline’s blood supply.

Recovery from Onion Poisoning in Cats

Although follow-up exams are rarely required, if your cat received a blood transfusion during treatment, the veterinarian may wish to reevaluate him. Depending on the extremities of your cat’s poisoning, improvement of condition may be seen within a few hours or a day after the treatment has been provided.

Prevention of Onion Poisoning in Cats

Avoid feeding your cat food scraps that may contain onions. Store your onions and other products containing onions in a place where your cat cannot access it. Do not leave your food uncovered or unattended as your cat may try to taste it.

If you love plants but have cats at home, check out these lists:

About the author

Clair Chesterman

Clair Chesterman is a professional cat breeder having her own cageless CFA and CCA Registered cattery & fostering company FluffyMeowPaws in Eugene, Oregon. Clair is a plant enthusiast too and she made in-depth research on toxic and non-toxic plants for cats.