A computer study of 11,574 cases revealed spinal block to be a safe procedure provided equipment is carefully cleaned, both the equipment and drugs are heat sterilized together in a tray, and the spinal block is administered with meticulous asepsis. In 8,852 patients, vasoconstrictor drugs were injected into the subarachnoid space along with the local anesthetic solution and they resulted in safe, consistent prolongation of anesthesia-epinephrine extended the duration by 50% and phenylephrine by 100%. Of the complications, hypotension was the most frequent. It occurred in 4,454 patients-1,225 prior to surgery and 3,229 during surgery. Headache resulted in 163 patients, backache in 48, postoperative vomiting in 233, peripheral nerve palsy in 17, but none were permanent. Prolonged spinal block occurred in 2 patients, and cardiac arrest occurred in four with 3 deaths.