INTRODUCTION: Active trachoma is caused by chronic infection of the conjunctiva by Chlamydia trachomatis, and is the world's leading infectious cause of blindness. Infection can lead to scarring of the tarsal conjunctiva, inversion of the eyelashes so that they abrade the cornea (trichiasis), and corneal opacity, leading to blindness. Trachoma is a disease of poverty, overcrowding, and poor sanitation. Active disease affects mainly children, but adults are at increased risk of scarring. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent scarring trachoma by reducing the prevalence of active trachoma? What are the effects of eye lid surgery for entropion and trichiasis? We searched: Medline, Embase, The Cochrane Library and other important databases up to January 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). RESULTS: We found 23 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. CONCLUSIONS: In this systematic review we present information relating to the effectiveness and safety of the following interventions: antibiotics, face washing (alone or plus topical tetracycline), fly control (through the provision of pit latrines, and using insecticide), health education, and lid surgery (bilamellar tarsal rotation, or tarsal advance and rotation).