Red fully ripened tomato in small amounts might be OK for your dog, however a warning about tomato is that it contains something called solanine which is present in the green leafy bits and possibly the unripened fruit of a tomato.
What is solanine?
Solanine occurs naturally in parts of several nightshade plants including potato, eggplant and tomato. It would likely only cause problems in your dog if eaten in large quantities, but if you want to be safe, avoiding tomato is recommended. Avoid letting your dog snack on the leafy bits of tomato plants in your garden if he/she should be so inclined to have a taste. Solanine is also found in potatoes that are exposed to sunlight for some time which causes the potato skin to turn a green-ish color.
Symptoms of solanine poisoning in a dog would likely be lethargy, vomiting, dizziness or diarrhea. There are other symptoms that might be apparent to a human experiencing solanine poisoning, but obviously your dog can’t describe in words how he/she is feeling, so you have to be observant of their behavior.
The purpose of this article isn’t to worry you about normal, ripened tomato, which as previously stated, shouldn’t cause a problem for a dog in small amounts. Canned tomato of any kind should be avoided as canned tomato usually had added salt and/or other preservatives. The discussion around any fruit or vegetable and dogs eating them should be tempered by the overall #1 point that dogs are primarily meat-eaters! The majority of your dog’s diet should consist of meat – everything else is a treat or snack to be enjoyed in small amounts.
What Other Fruits or Veggies Can I Feed My Dog?
Read more here about other fruits and vegetables you might be inclined to offer your dog as a treat.
Disclaimer: As this article refers to health and diet related topics that affect your dog’s well being it should be pointed out that WagWagWoofWoof.com, and the authors here are NOT veterinarians. The information in this article and others on this site is based upon research we have found both online and in print, summarized here for convenience, discussion and a starting point for further reading. Use information found here at your own discretion and risk.