Can Dogs Eat Cucumber?

Cucumber is a safe vegetable for dogs

Cucumber is one of the gentler vegetables a dog can eat. It isn't toxic the way chocolate or grapes are, it has virtually no fat, and it's low in sodium. About 96% of its weight is water, so it's extremely low in calories — the American Kennel Club puts half a cup of cucumber slices at roughly 8 calories. For comparison, a typical dog biscuit runs around 40 calories.

That makes cucumber useful in two situations in particular. The first is summer hydration: it's crisp and cooling, and a good thing to let your dog chew on when it's hot out. The second is treating a dog who's on a weight-loss plan. Cutting treats out entirely is hard on both dog and owner, and cucumber lets you keep the ritual without the calories. Do keep in mind that the vitamin K, C and B content isn't a reason to feed it — a dog on complete and balanced food is already getting those nutrients, so there's no need to push cucumber on a dog who doesn't want it.

Rules to follow when you serve it

• Cut it into bite-sized pieces — a whole cucumber, or a long spear, is a choking hazard. That's especially true for small dogs and for dogs who gulp their food. Thin slices about 5 mm thick, or small cubes, are safest.
• Peeling and deseeding is the safer option — the skin is tough and not easy to digest, and it may carry wax coating or pesticide residue. If the cucumber has large seeds, scrape out the center as well. If you do serve it with the skin on, scrub it and rinse it thoroughly under running water first.
• Plain and raw only — no salt, vinegar, sesame oil or sugar.
• Start with one or two pieces — wait a day to make sure there's no diarrhea or vomiting before increasing the amount.

How much per day?

The general rule is that treats shouldn't exceed 10% of a dog's daily calories. Cucumber is so low in calories that you'll almost never hit that ceiling — but it is high in water and fiber, so too much brings loose stool or diarrhea. With cucumber it's more practical to think in terms of volume than calories.

• Small dogs (around 5 kg): 3–5 thin slices per day (about 20–30 g)
• Medium dogs (10–15 kg): 6–10 thin slices per day (about 50–80 g)
• Large dogs (25 kg and up): 100–150 g per day

If you want to know your dog's daily calorie needs, our dog food portion calculator will work it out. Ten percent of that number is your limit for all treats combined — not for cucumber on its own, so count everything else you gave that day too.

Pickles and seasoned cucumber are a firm no

In practice, the problems with cucumber almost never come from plain cucumber — they come from the cucumber dishes people eat. Pickles are extremely high in sodium and can cause thirst, vomiting and diarrhea even in small amounts. More important still is the garlic and onion that go into most cucumber salads and relishes. Both destroy a dog's red blood cells and can cause anemia, and cooking does not remove that toxicity. If your dog grabbed a piece of seasoned cucumber off the table, note how much and when, and call your vet.

For a fuller list of what dogs should never eat, see Foods Dogs & Cats Can't Eat — Complete Guide.

When to be extra careful

If your dog already has a sensitive stomach and often passes soft stool, a watery, fibrous vegetable like cucumber can be a burden — start with a very small amount. If your dog is being managed for kidney or heart disease, where fluid and electrolytes matter, talk to your vet before adding any new treat. And for a senior dog with weak teeth, a thin slice left out of the fridge for a few minutes is easier than a hard, ice-cold chunk. If your dog vomits repeatedly after eating cucumber, it may not be simple indigestion — our guide to dog vomit colors and what they mean is worth a read.

🔗 Related articles

• Can Dogs Eat Watermelon?
• Can Dogs Eat Apples?
• Summer Dog Walks — Avoiding Hot Pavement Burns
• Foods Dogs & Cats Can't Eat — Complete Guide