Orexigenic describes any substance, signal, or stimulus that increases appetite and drives food intake. The body’s own orexigenic signals include the stomach hormone ghrelin, which rises before meals, and the brain peptide neuropeptide Y, both pushing the organism toward eating. Certain medicines have orexigenic side effects, notably some antipsychotics, antidepressants, and corticosteroids, which is clinically useful in wasting conditions but problematic in obesity-prone patients. Cannabinoids are famously orexigenic, the basis of both the “munchies” and prescribed appetite stimulants for HIV and cancer cachexia. In food product development, orexigenic cues are engineered deliberately: appealing aromas, varied textures, and palatable flavours all stimulate the desire to eat, which is why the concept matters as much to marketing as to medicine.