In an attempt to reduce oedema of the arm after mastectomy, patients were provided with an elastic sleeve which was worn for a period of between 1 week and up to 6 months. A statistically significant mean relative decrease of 17% in the volume of oedema was achieved. Subsequent treatment by intermittent pneumatic compression for 10 days produced a further significant mean relative decrease of 18%. When the sleeve was worn for 6 months after this treatment there was no significant increase in arm volume--that is, no relapse.