Mr. Peng, 68, was diagnosed with prostate cancer four years ago. After endocrine treatment and radiotherapy, his condition was once effectively controlled. However, two years ago he began to experience pain in multiple places throughout his body and was diagnosed with multiple bone metastases throughout his body after a bone scan. The doctor prescribed him oral pain medication, along with other symptomatic treatments. However, as his condition progressed, Mr. Peng’s pain worsened and the pain medication was increased to 6~8 tablets/day, and he still woke up in pain at night. His wife brought him to the pain department of Peking University Hospital, where the doctor told him that the pain medication had reached the maximum dose and reached the “ceiling” (i.e. the capping effect), and that he needed to switch to a stronger drug, an opioid painkiller. The doctor prescribed oxycodone hydrochloride extended-release tablets for Mr. Peng and advised him to start taking 20 mg and adjust the dose according to the analgesic effect and side effects. Since then, Mr. Peng’s wife has been coming to the pain department regularly for prescriptions, reporting his recent analgesia to the doctor and adjusting the dosage of the medication under the doctor’s guidance. Last week, Mr. Peng’s wife came to pick up his medication again and brought the not-so-good news that Mr. Peng could no longer walk and was completely bedridden, relying on his wife to take care of his daily life. Due to the progression of the disease and the increasing pain, the dosage has now been increased to 120mg/time, twice daily. The couple did not dare to increase the dosage without permission, fearing that there would be no more medicine available for future pain. The physician explained that opioids do not have a capping effect and patients do not need to tolerate pain. If the pain worsens later or if they cannot take oral medication, they can combine other medications for analgesia, and there are also transdermal patches and intrathecal morphine pumps for analgesia. Under the present circumstances, as long as the comorbidities of the medication such as constipation are dealt with, it is completely safe to increase the dose to achieve effective analgesia, which is very meaningful to improve Mr. Peng’s quality of life. In their clinical work, pain physicians have seen too many misconceptions about opioid analgesia. Many patients think that taking opioids is drug addiction, fearing addiction, or are too afraid to take them for fear of side effects, and suffer from pain alone, which seriously affects the quality of life. Cancer pain is the most diverse and complex type of pain in terms of mechanism. With the aggravation of the disease, cancer tumors spread and metastasize to bones, nerves and internal organs, etc. Patients in advanced stage often find it difficult to tell the exact location and degree of pain, but just feel unbearable pain. Pain can also cause adverse implication of recurrence or aggravation of the disease, make patients pessimistic and desperate, and lose confidence in treatment, which affects the effect of anti-tumor treatment and patients’ quality of life. Desperate patients and family members who cannot effectively control cancer pain may seek informal treatment or even seek euthanasia with the help of doctors. Pharmacological analgesia is the basis and effective method for treating cancer pain. Through drug treatment, more than 80% of cancer pain patients can get more satisfactory relief, while for patients who are not satisfied with the effect of drug treatment, minimally invasive interventional therapy, radiotherapy, chemotherapy and hormone therapy can be considered. Although morphine consumption in China has gradually increased in the last decade or so, cancer pain treatment in many regions is still inadequately treated, among which poor compliance of cancer pain patients and their families is the most important factor affecting pain treatment.