Toxic plant alkaloids are found in all parts of the tomato plant. Ripe tomatoes have the least amount of these compounds and are considered non-toxic. Companion animal or livestock that ingest large amounts of green tomatoes, leaves, or stems may develop gastrointestinal distress (e.g., vomiting, diarrhea) and neurological signs (e.g., weakness, lethargy, stumbling, disorientation).