Pain management, pain killer, pain medicine, pain control or algiatry, is a branch of medicine that uses an interdisciplinary approach for easing the suffering and improving the quality of life of those living with chronic pain. Medicine treats injuries and diseases to support and speed healing. It treats distressing symptoms such as pain to relieve suffering during treatment, healing, and dying. The task of medicine is to relieve suffering under three circumstances. The first being when a painful injury or pathology is resistant to treatment and persists. The World Health Organization (WHO) recommends a pain ladder for managing pain relief with pharmaceutical medicine. It was first described for use in cancer pain. However it can be used by medical professionals as a general principle when managing any type of pain.