If the patient has generalized pain after chemotherapy, he/she can take painkillers to control it. Because generalized pain after chemotherapy belongs to one kind of cancer pain, cancer pain is now clinically treated as a kind of disease and needs to be effectively treated. Cancer pain means all the pains occurring in cancer patients belong to cancer pain, which can be categorized into mild cancer pain, moderate cancer pain and severe cancer pain according to different degrees, and different analgesic drugs can be chosen for treatment according to different degrees of cancer pain. For mild pain, that is, cancer pain with a score of 1-3, antipyretic and analgesic drugs need to be given for treatment. For cancer pain greater than or equal to a score of 4 or more, i.e., moderate and severe cancer pain, opioids are currently given to treat the pain, and for moderate pain, low-dose opioids are given to treat the pain.