Dogs can eat tomatoes, but only in small amounts and only when the tomatoes are ripe and red. Ripe tomatoes are generally safe and non-toxic for dogs, but green tomatoes, tomato stems, leaves, and other parts of the tomato plant contain toxins like solanine and tomatine, which can be harmful to dogs. Feeding dogs unripe tomatoes or parts of the tomato plant can lead to tomatine poisoning. Tomatoes can be a healthy treat for dogs in moderation since they contain vitamins and antioxidants like vitamin C, potassium, and lycopene. However, tomato-based products like sauces or canned tomatoes that contain additives like salt, garlic, or onions should be avoided as they can be toxic to dogs. In summary: dogs can safely eat small amounts of ripe, red tomatoes occasionally, but it is important to avoid unripe tomatoes, tomato leaves, stems, and any seasoned tomato products.