Not recommended — dogs and prunes
Not recommended. Prunes — dried plums — have three strikes: they’re extremely high in sorbitol which acts as an osmotic laxative and causes diarrhoea in dogs; they’re concentrated in sugar (38g per 100g) from the drying process; and the pits (if present) contain amygdalin, a cyanogenic glycoside that releases hydrogen cyanide when metabolised. One pitted prune accidentally eaten is unlikely to cause serious harm in a large dog, but prunes are not a snack, a treat, or a constipation remedy for dogs.
🏆 PawKeen Safety Score™ — Prunes for Dogs
“Prunes as a dog constipation remedy — this one comes up semi-regularly, usually suggested to owners by well-meaning friends or a quick internet search. The idea behind it is correct in the sense that prunes do make things move — sorbitol is an osmotic agent that draws water into the intestine. But for a dog, this is the same mechanism that causes diarrhoea, not constipation relief in a controlled way. There’s no dose guidance for prunes in dogs, the sugar content is high, and the pits in unpitted prunes are a real hazard. If a dog needs help with constipation, I recommend plain canned pumpkin puree (not pie filling) — it’s high in fibre, well-tolerated, and has established use in canine gastroenterology. Not prunes.”
Prunes are not a safe constipation fix for dogs
This is the question behind the question almost every time prunes come up in consultation. Someone’s dog is constipated. Someone else told them prunes work for constipation in humans, so why not dogs? The logic seems reasonable.
The problem is that prunes don’t work for constipation in dogs the same way they work in humans — they just cause diarrhoea. And the tools for properly managing canine constipation are available and safe. Prunes are not one of them.
What sorbitol does and why it’s not a “gentle laxative” for dogs
Sorbitol is a sugar alcohol — the same family as xylitol, though with different toxicity mechanisms. In humans, sorbitol causes a laxative effect through osmosis: it draws water into the intestinal lumen, softening stool and promoting bowel movements. This is useful for human constipation.
Dogs have a similar osmotic response to sorbitol. But they’re smaller, and the threshold between “gentle laxative” and “persistent watery diarrhoea” is much harder to calibrate. Prunes contain approximately 14.7g of sorbitol per 100g — a very high concentration. Even a couple of prunes in a small to medium dog delivers a sorbitol dose that causes liquid diarrhoea rather than soft, easy-to-pass stool.
The outcome is the dog going from uncomfortable constipation to uncomfortable diarrhoea. Neither is the resolution you were hoping for.
The dried fruit sugar concentration problem
Fresh plums contain approximately 10g of sugar per 100g. When you dry a plum to make a prune, most of the water is removed — you’re left with the same total sugar in a fraction of the weight. Dried prunes contain approximately 38g of sugar per 100g — nearly four times the concentration of the fresh fruit.
This matters because dogs eating prunes will eat them quickly without understanding the difference between the water content of fresh fruit and dried fruit. A dog that would eat three plum halves and feel satisfied might eat ten or twelve prunes before slowing down — consuming far more sugar than their system can handle efficiently. The GI consequences (vomiting, diarrhoea) are compounded.
High sugar fruit causes rapid fermentation in the large intestine in significant amounts — gas, bloating, and loose stools follow.
The pit problem: amygdalin and cyanide
Fresh plums and prunes both have pits. Some prune products are pitted (the pit has been removed); many traditional prunes still contain the pit.
Plum pits contain amygdalin — a cyanogenic glycoside. When the pit is broken, chewed, or metabolised, amygdalin is hydrolysed to release hydrogen cyanide. Dogs can chew through plum pits if motivated.
The cyanide from a single cracked plum pit in a medium-large dog is unlikely to cause serious toxicity — the dose is low. But it’s not zero, and signs of cyanide poisoning (rapid breathing, bright red gums, weakness, dilated pupils) are dramatic and distressing when they occur. A small dog chewing through multiple pits is a more serious scenario.
The safe rule: if prunes are in the house and the dog has any chance of accessing them, ensure they are pitted or stored completely out of reach.
Better alternatives for dog constipation
| Approach | How it works | Evidence base |
|---|---|---|
| Canned pumpkin puree (plain) | High soluble fibre, water content | Widely used in canine GI management |
| Psyllium husk (small amount) | Fibre supplement, adds bulk | Vet-recommended with adequate water intake |
| Increased water intake | Softens stool directly | Core intervention for constipation |
| Plain cooked sweet potato (small amount) | High fibre and water | Generally well-tolerated |
| Prunes | Causes diarrhoea via sorbitol | Not appropriate — unpredictable |
If your dog is constipated and home measures haven’t resolved it within 24–48 hours, see a vet — constipation in dogs can indicate an underlying issue (dehydration, obstruction, megacolon, or other conditions) that needs examination.
🚨 My Dog Ate Prunes — What Now?
If your dog ate prune pits (whole or cracked) and is showing breathing changes, bright red gums, or neurological signs, call the Animal Poisons Helpline on 1300 869 738 immediately — this may indicate cyanide toxicity. For pitted prune flesh with diarrhoea: supportive care at home, call your vet if diarrhoea is bloody or persists beyond 24 hours.
Signs that warrant a vet call:
- Loose stools or diarrhoea from sorbitol — begins within a few hours of eating prunes. With pits: watch for signs of cyanide exposure — rapid breathing
- bright red gums
- dilated pupils
- weakness
- disorientation. Large amounts of pitted prune flesh can also cause vomiting and diarrhoea from the concentrated sugar
If your dog ate a large amount or is showing the signs above: Don’t wait — call immediately.
📞 Animal Poisons Helpline: 1300 869 738
Available 24/7 across Australia. Have your dog’s weight, breed and approximate quantity consumed ready when you call.
Frequently Asked Questions
Prune juice concentrates the sorbitol and sugar further. A dog drinking prune juice will have rapid, dramatic diarrhoea. This is not medically dangerous in a healthy adult dog (the diarrhoea will resolve), but it’s unpleasant and definitely not a controlled constipation treatment.
For more on fruit safety for dogs, see our dog food safety hub and our guides on can dogs eat pears and can dogs eat mulberries.
📚 Sources & Further Reading
- Bischoff K, Perelman B. Cyanogenic plant poisoning. In: Plumlee KH, ed. Clinical Veterinary Toxicology. Mosby, 2004.
- ASPCA Animal Poison Control — Stone Fruits and Cyanogenic Plants. https://www.aspca.org/pet-care/animal-poison-control
- Hall EJ, German AJ. Diseases of the small intestine. In: Ettinger SJ, ed. Textbook of Veterinary Internal Medicine. 2010.
- Australian Veterinary Association — Fruit Safety for Dogs. https://www.ava.com.au
