吗啡多经由注射给药，但口服也有效。最大的缺点是易成瘾，虽然短期使用很少导致药物成瘾，许多医生仍避免使用能缓解剧烈疼痛的剂量。

• "Morphine is usually given by injection but may be taken by mouth. Its most serious drawback is its addictiveness; many doctors are reluctant to use amounts adequate to relieve severe pain, even though short-term use in such cases rarely leads to drug addiction."