Verwoerd JH. The secrets of sciatica. Huisarts Wet 2016;59(3):105-7. Lumbosacral radicular syndrome (sciatica) is common and causes significant disability, but crucial aspects of our knowledge of its aetiology, treatments, and prognosis lack a firm scientific basis. It has several potential causes, such as inflammation and disc herniation. While general practitioners and patients often talk about a ‘herniated or slipped disc’, this diagnosis cannot be made on the basis of the patient history and physical examination alone but requires imaging. However, some patient information may be suggestive of a hernia, such as a body mass index lower than 30, non-sudden onset, sensory loss, and worsening of leg pain on coughing, sneezing, or straining. The only predictor of the need for surgery is the severity of the leg pain; other factors that influence the prognosis have not yet been identified. There is a need for research not only into the role of inflammatory factors but also into the effectiveness of common treatments, such as analgesics and physiotherapy, and into patient subgroups that might benefit from a particular treatment approach. Such research should especially be done in primary care.