A morphinane alkaloid that is a highly potent opiate analgesic psychoactive drug. Morphine acts directly on the central nervous system (CNS) to relieve pain but has a high potential for addiction, with tolerance and both physical and psychological dependence developing rapidly. Morphine is the most abundant opiate found in Papaver somniferum (the opium poppy). (Chemical Entities of Biological Interest Ontology, CHEBI_17303)