Life is mostly plants. Plants constitute an estimated 80% of the biomass on Earth and are concentrated in terrestrial environments. Millions of animal species rely on plants to survive and the organismic design of plants and animals have been tightly interwoven in intricate ways over evolutionary time. Humans are no exception. Plants have been a foundational component of human diets across evolutionary time, yet many plants can be toxic or even fatal if ingested. In this talk, I will present research exploring the cognitive systems human infants use to negotiate this paradox and learn which plants they can safely eat.