1. Drug simplification involves removing unnecessary structural groups from complex lead compounds to improve synthetic accessibility, pharmacokinetic profiles, and reduce side effects. 2. The steps of drug simplification include analyzing molecular complexity, determining important substructures, elucidating structure-activity relationships, and removing unnecessary motifs. 3. Simplification of morphine involves sequentially removing rings, from E to BCDER. This demonstrates that certain rings like the oxygen bridge are not essential for analgesic activity. Simplified analogues like benzomorphans and pethidine retain analgesic properties.