Tomatoes?

What to watch out for

Ripe red tomatoes are considered non-toxic to dogs and can be fed in moderation as an occasional snack. The concern is the rest of the plant. Tomato stems, leaves and unripe green fruit contain solanine and tomatine, which are found mostly in the green parts of the plant and can cause vomiting, diarrhea, muscle weakness and loss of coordination.

Poisoning is rare in dogs and usually is not fatal, but smaller dogs and puppies can be affected by a smaller amount. In practice, problems come from dogs raiding a garden and eating vines or green tomatoes, not from a slice of ripe tomato. Too much tomato can also upset the stomach because of its acidity.

Only serve plain fresh tomato. Tomato sauce and ketchup often contain garlic and onions, which can cause stomach problems, so dogs should not eat them. If you grow tomatoes, fence the plants or keep your dog out of that part of the garden.

What to give instead

Choose a ripe red tomato, wash it, remove the stem and any green parts, and dice the flesh into small pieces. Start with a small amount and watch for a reaction. Treats should be no more than 10% of daily calories.

• Small dogs: one or two small pieces
• Medium dogs: a few pieces
• Large dogs: a few more pieces, occasionally

If your dog has a sensitive stomach, skip it. There are gentler vegetable treats, such as cucumber.

If your dog already ate it

A bite of ripe tomato is nothing to worry about. If your dog ate tomato leaves, stems, vines or green tomatoes, watch for vomiting, diarrhea, weakness or loss of coordination, and call your vet or a poison line, especially if your dog is small.

In the US: ASPCA Animal Poison Control (888) 426-4435 or Pet Poison Helpline (855) 764-7661 (fees may apply); elsewhere, your local emergency vet. Do not induce vomiting at home. Mention what part of the plant was eaten and roughly how much.