Pet Poison Prevention Week continues, and today’s focus is grapes, raisins, and currants, which can cause kidney failure and even death in dogs. That includes oatmeal raisin cookies, cinnamon raisin bagels, trail mix, raisin bran… lots of human foods that an undiscerning dog may gobble up are potential toxins.
What are raisins, and currants?
Raisins and currants are types of dried grapes, each with their unique characteristics. Raisins are grapes that have been left to dry for about three weeks. They are a dark brown color. Sultanas, often referred to as "golden" raisins, are dried green seedless grapes and are typically lighter in color than raisins. Currants, also known as " Corinth raisins, Corinthian raisins and Zante currants," are tiny, dried grapes that are not to be confused with berries like Ribes sativium and Ribes nigrum that are also called "currants."
Can dogs eat currants, grapes, or raisins?
No, dogs should not eat currants or raisins. Raisins, currants as well as grapes are bad for dogs. They can cause severe health issues in your pets, including kidney failure and even death. As mentioned, dogs should not eat grapes. Whether they're seedless or seeded, commercial or homegrown, red or green, organic or non-organic, they can pose a risk to dogs. Even grape pressings from wineries can be harmful.
Poisoning has occurred in dogs following ingestion of seedless or seeded grape varieties, commercial or homegrown fruits, red or green grapes/raisins, organic or non-organic fruits, and grape pressings from wineries. (While not established as a cat toxin, there have been anecdotal reports of cats and ferrets being affected too, so keep grape, raisin and currant treats away from all of your four-legged friends).
Will my dog be OK if he eats only one grape/raisin/currant?
Unfortunately, there is no well-established toxic dose for any of these fruits, but two principles seem to prevail: 1) Dogs are more likely to become poisoned if they ingest large amounts of fruit and 2) there is significant individual sensitivity amongst dogs. Some dogs appear to tolerate small doses of the fruit without consequence while other dogs may develop poisoning after the ingestion of just a few grapes or raisins. There is no way to predict which dogs may be more sensitive. Raisins are more concentrated than grapes, so are believed to be more dangerous.
Why Are These Fruits Toxic to Dogs?
Currently, it is not known why these fruits are toxic. Some researchers suspect that a mycotoxin (a toxic substance produced by a fungus or mold) may be the cause. Some suspect a salicylate (aspirin-like) drug may be naturally found in the grape, resulting in decreased blood flow to the kidneys. However, so far no toxic agent has been identified. Since it is currently unknown why these fruits are toxic, any exposure should be a cause for concern.
Symptoms & Course of Action
The most common early symptom of grape or raisin toxicity is vomiting, which is generally seen within 24 hours following ingestion. Lack of appetite, lethargy, and possibly diarrhea can be also seen within the next 12-24 hours. More severe signs are not seen for 24-48 hours after ingestion – often after acute kidney failure has already begun. Signs of acute kidney failure include nausea, lack of appetite, vomiting, uremic breath, diarrhea, abdominal pain, excessive thirst, and excessive urination.
If you suspect that your pet has eaten any of these fruits, please contact your veterinarian (or your closest 24-hour emergency clinic) immediately. Do not waste any time; since there are still many unknowns associated with this poisoning, it is better not to take chances. As with any toxin, the sooner the poisoning is diagnosed and treated, the less dangerous it is for your pet, and the less expensive therapy will be for you.
Treatment and prognosis
Your veterinarian will take immediate action to block absorption of the toxins (by inducing vomiting and administering activated charcoal) and to prevent or minimize damage to the kidneys (by aggressively administering intravenous fluids to flush any absorbed toxins out of the body and using medications to help maintain kidney function). They will also recommend diagnostic blood tests to assess the amount of damage to the kidneys, which will help determine the dog’s likelihood of recovery.
Prognosis depends on many factors, including how severe the poisoning was, whether treatment was initiated soon enough to block absorption of any of the toxins, whether or not they have already developed kidney failure, and whether the clinical signs and kidney values improved once treatment was started. If a dog only ate a few grapes or raisins (depending on the size of the patient) and received immediate treatment, their prognosis is excellent. However, if their kidneys are damaged and no urine is being produced, their prognosis is poor, and fatality is likely.
Prevention is Key
Prevention is the best medicine! Always keep grapes, raisins, currants, and treats containing these fruits securely locked away from your pets!
If you think your dog has ingested any amount of grapes, currants or raisins, please contact us immediately.
Journal of Veterinary Internal Medicine "Toxicosis with grapes or raisins causing acute kidney injury and neurological signs in dogs"
American Kennel Club "Can Dogs Eat Grapes"
Purina "Can Dogs Eat Grapes or Raisins"
WebMD "Why Dogs Can't Eat Grape"
Healthline "Can My Dog Eat This? A List of Human Foods Dogs Can and Can't Eat"