The important principle in conservative treatment is immobilization of the spine and relief of weight bearing by rest in bed, which relieves to some extent the extruding tension on the prolapse and so gives the ligaments or nerve root time to adapt themselves to the pressure. Traction on the leg by means of a weight and adhesive strapping is sometimes beneficial in some cases with very severe pain. It is important that analgesic drugs be administered in adequate quantities to make the pain bearable. an adequate trial of conservative treatment. Physiotherapy . (ii) Recurrent attacks of pain. Operation is usually advised at the start of a second attack if the first episode has been severe, but the decision must be left to the patient, who may wish to give conservative treatment a further trial. (iii) Cauda equina compression or severe foot drop. With regard to sciatica the indications under (i) and (ii) above are quite straightforward, but when operation is contemplated for a prolapse causing low back pain alone, stricter criteria are necessary.