Can dogs eat lemon?

The detail

Lemons sit in the red tier for a practical reason rather than a dramatic one. Nothing in a lemon is going to kill a dog the way a handful of raisins might, but there is no version of feeding one that leaves the dog better off.

Vets Now states that the plants and rinds of lemons and limes contain linalool, limonene and the phototoxic compound psoralen, all of which can be toxic for dogs in large quantities. Those compounds concentrate in the peel and pith rather than the juice.

The flesh is a different problem: sour enough that most dogs drool, gag or back away from it. That reaction is the sensible one, and the videos of dogs being handed lemon wedges are worth skipping rather than copying.

The genuinely serious end of this subject is not the fruit at all. Lemon essential oil and citrus-scented cleaning products are far more concentrated, and both VCA Animal Hospitals and the Pet Poison Helpline treat them as a poisoning risk.

What is actually in a lemon

A lemon is about 5 percent citric acid by weight, which is what gives it a pH of around 2 and makes it roughly as acidic as vinegar. That acidity is the reason a dog drools and backs off, and the reason a swallowed mouthful can come back up an hour later.

The peel and pith hold the oils. Limonene makes up most of the oil in citrus rind, linalool sits alongside it, and psoralen is the phototoxic compound Vets Now names in the same breath. All three are in the rind, not the juice, which is why the peel is the part to worry about.

There is nothing on the other side of the ledger. The vitamin C that sells lemons to people is made in a dog's own liver, so a lemon is acidity and oils with no nutritional argument attached.

Lemon flesh and juice

Lemon flesh is sour enough that a dog's first response is usually drooling and lip smacking, followed by walking away. That is a reaction to the citric acid, and it is doing exactly the job it should.

A dog that does swallow some can end up with vomiting or diarrhoea a few hours later, and small dogs get there on smaller amounts. A drop of juice splashed on the floor is nothing to panic about, but a chewed wedge is worth a watchful evening.

There is no upside to weigh against it. Dogs make their own vitamin C, so the human argument for citrus does not apply.

Lemon peel and pith

The peel is the worse part of the fruit. It holds the citrus oils in their most concentrated fruit form, and those are the compounds Vets Now names as toxic to dogs in quantity.

Peel also digests badly. A strip swallowed by a small dog can lodge in the gut, and a whole lemon eaten skin and all is worth a phone call rather than a wait.

Wedges left in the bottom of a glass or on the edge of a plate are the usual route in. Bin them rather than leaving them at nose height.

Can dogs eat limes?

Same fruit family, same answer, same reasons. Vets Now covers lemons and limes together because both carry linalool, limonene and psoralen in the plant and rind.

Limes turn up around dogs in gin glasses and takeaway boxes, where the alcohol or the spicing is often the bigger issue. Treat a chewed lime the way you would a chewed lemon and ring your vet if peel went down.

Lemon in water and lemonade

Lemon in your dog's water bowl does nothing useful and puts many dogs off drinking, which is the opposite of what you want in hot weather. Plain water is the whole answer.

Lemonade and lemon squash add sugar to a drink a dog has no need for. Sugar-free versions deserve extra care, because some sweeteners intended for people, xylitol in particular, are severely toxic to dogs.

Lemon essential oil and cleaning products

This is the part of the subject that genuinely matters. VCA Animal Hospitals lists citrus oil among the essential oils poisonous to dogs and says both ingestion and skin exposure can be toxic, with tremors, vomiting and burns on the lips, gums or tongue among the signs.

Keep lemon oil bottles, diffusers and citrus-scented cleaners out of reach, and do not put any of it on your dog's coat or skin. If there has been contact or a spill your dog has walked through, ring your vet rather than washing it off and hoping.