We studied the effect of the addition of hyaluronidase to a mixture of lignocaine 2% and bupivacaine 0.75% for peribulbar anaesthesia in 60 patients presenting for elective intra-ocular surgery. Using a randomised, double-blind design, patients were allocated to one of three groups: no hyaluronidase (group A) (n = 20); hyaluronidase 50 iu.ml-1 (group B) (n = 20); hyaluronidase 150 iu.ml-1 (group C) (n = 20). The speed of onset of the block, the presence of akinesia, analgesia and the need for supplementary injections were assessed. The addition of 150 iu.ml-1 of hyaluronidase resulted in a mean (SEM) time to akinesia of 9.2 (0.9) min compared to 10.9 (0.9) min in the control group and 10.7 (1.1) min in those receiving the lower dose. Fewer patients in group C required a further injection (20%) than those in groups A (40%) or B (45%). None of the findings were statistically significant. Hyaluronidase was not associated with any complications.