CART peptides are novel, putative brain-gut neurotransmitters and co-transmitters that probably have a role in drug abuse, the control of feeding behavior, sensory processing, stress and development. They are abundant, processed and apparently released. Exogenously applied peptides cause inhibition of feeding and have neurotrophic properties. Although the precise sequences, relative abundance and efficacy of all CART peptides are currently being determined, small molecules that are active at putative CART receptors could have substantial therapeutic promise.