Anal submucosal injection: a new route for drug administration. VI. Chronic prostatitis: a new modality of treatment with report of eleven cases. The anal submucosal route was used for the treatment of chronic bacterial prostatitis in 11 patients. Prior to presentation, the patients had received different antimicrobial agents; the symptoms disappeared only to recur whenever the drug was discontinued. After repeated failure, the patients were treated with gentamicin to which the organisms were sensitive, via the anal submucosal route. A daily injection was given for ten days on an outpatient basis. The technique of injection is described. The patients were followed up clinically and by segmented cultures for three years. No anorectal complications were encountered as had been demonstrated experimentally. The symptoms of chronic prostatitis disappeared, and culture was negative by the end of treatment and for two to three years thereafter in all patients. It appears that the antimicrobial agent, via anal route, reaches the prostatic tissues at a higher concentration than that of the serum. The route adopted by the drug to reach the prostate from the anal submucosa is presented. 