From Wikipedia: Like many other nightshades, tomato leaves and stems contain atropine and other tropane alkaloids that are toxic if ingested. Ripened fruit does not contain these compounds. Leaves, stems, and green unripe fruit of the tomato plant contain small amounts of the poisonous alkaloid tomatine. Use of tomato leaves in tea (tisane) has been responsible for at least one death. However, levels of tomatine are generally too small to be dangerous.