We included 12 studies with altogether 671 participants. Two high quality randomized controlled trials with altogether 141 participants demonstrated clinical improvement of carpal tunnel syndrome at one month or less following local corticosteroid compared to placebo injection ( relative risk (95% confidence intervals to )). One trial compared local corticosteroid injection to oral corticosteroid and at 12 weeks after treatment there was significantly more improvement in the injection group ( mean difference - (95% confidence intervals - to -)). In one trial , the rate of improvement after one month was greater after local than systemic corticosteroid injection ( relative risk (95% confidence intervals to )). In one trial , symptoms did not improve significantly more in the injection group at eight weeks after injection compared to treatment with anti-inflammatory medication and splinting ( mean difference (95% confidence intervals - to )). Two injections versus one injection of local corticosteroid did not provide further clinical improvement, mean difference - (95% CI - to ).