In addition to humanitarian reasons for improving acute pain management, there is now evidence justifying that unrelieved acute pain may result in harmful physiological effects. These effects may results in significant morbidity and even mortality. Despite recent advances in surgery and anesthesia many patients continue to experience unpleasant pain during the early postoperative period. So, why do patients have to continue to suffer from acute pain whenever effective opiate analgesics are available? The primary reason may relate to a lack of information about analgesic drugs and misconception about their potency, duration of action, side effects, and addictive potential. As a result many patients are prescribed dosages of analgesics that are less than half of what is actually needed to relief their pain. Patient-controlled analgesia (PCA) infusion devices allow patients to self-administer narcotic analgesics within the limits prescribed by the physician. PCA therapy is typically used for postoperative, obstetric, terminally ill, and trauma patients. PCA pumps deliver solutions intravenously, subcutaneously, or epidurally and allow patient activation by means of pendant button on a cord connected to the pump or a button directly on the pump.Patient-controlled intravenous analgesia (PCIA) was given a trial in the late 1960s but never became established as a method of labor analgesia because of the poor efficacy of intravenous opioids, neonatal effects and cost. It continues to be reserved for situations in which regional analgesia is either contraindicated (e.g. severe preeclampsia with profound thrombocytopenia) or technically difficult (e.g. musculoskeletal deformity, previous spinal surgery). Patient controlled epidural analgesia (PCEA) seems likely to increase in use because it fulfills many of the requirements identified as important for maternal satisfaction during childbirth. These requirements include the feeling of control (control of panic, pain, and involvement in decision making) and the psychological benefits of having immediate access to epidural solution and self-titration to individually determined endpoints.