OBJECTIVE: To investigate whether hyaluronidase (Hyalase) is a useful and justified addition to haematoma block for pain relief. METHODS: The study was a randomised double blind trial of 33 consecutive patients attending the accident and emergency department for manipulation of distal radius fracture under haematoma block. Control patients received 1% lignocaine; the treatment group received 1% lignocaine plus 1500 IU hyaluronidase. Manipulation occurred 10 minutes after instituting the block. RESULTS: 16 patients received hyaluronidase, 17 received lignocaine only. One patient with unsuccessful manipulation was excluded. There was no significant difference between the two groups for any of three methods of pain assessment (P > 0.05, Mann Whitney). CONCLUSIONS: The addition of hyaluronidase does not increase the efficacy of the haematoma block when 10 minutes are allowed to elapse before manipulation, and the increased cost of adding (and risk of allergy) is not justified by any theoretical increased speed of analgesia.