Prolotherapy is a controversial treatment for chronic low back pain involving repeated injections of tender ligaments with a solution of 15-20% glucose and 0.2% lignocaine. It aims to stimulate inflammation and subsequently to strengthen ligaments, leading on to a reduction in pain and disability. This paper presents the results of a multicentre pilot study comparing the effectiveness of prolotherapy with a range of other conservative treatments used in clinical practice for the treatment of chronic low back pain. The median percentage reductions in outcome measures (interquartile range) from baseline to three months for patients treated with prolotherapy (n=20) versus those treated with other therapies (n=13) were as follows - visual analogue back pain scores: 60% (46%, 78%) vs 40% (-8%, 56%); visual analogue leg pain scores; 76% (40%, 100%) vs 2% (- 8%, 67%); pain diagram scores; 37% (17%, 77%) vs 12% (-32%, 37%); and Roland-Morris disability scores; 43% (13%, 88%) vs 31% (-38%, 55%). This trial was conducted as a pilot study for a randomised controlled trial examining the efficacy of prolotherapy injections, saline injections and exercises in the treatment of chronic low back pain.