The taste and smell of food can evoke strong memories. The strength and importance of food-learning makes it a good system to explore the behavior, neurology, and molecular biology of learning and memory. I use a simple but robust model of learning: conditioned taste aversion, in which rats learn to reject a palatable solution after it is paired with a toxin (LiCl). Behavioral studies are combined with brain lesions, neuroanatomical imaging, and single-cell RNA amplification to study the patterns of gene expression underlying long-term changes in the rat's ingestive behavior.