Opiate detoxification using methadone programmes are inefficient and expensive. Rapid and ultra-rapid detoxification using precipitated withdrawal under heavy sedation or anaesthesia provide increased efficiency and speed, but are limited by the requirement for high-dependency facilities and are perceived as high-risk procedures. Procedures using precipitated withdrawal over longer periods with lower sedation are safer, but 20% of patients fail to tolerate these. Here we evaluate a naltrexone compressed opiate detoxification (NCOD) protocol. We investigated patient acceptance, organ function and abstinence rates on 504 consecutive patients undergoing treatment at the Harrogate Detox5 centre between February 1996 and January 1999. Ninety-eight per cent of patients completed the procedure; 81% of patients reported withdrawal was "better than expected". Only 3% of patients reported any pain. Laboratory investigations demonstrated no organ dysfunction. Abstinence rates post-detox were high with 71%, 61% and 51% of patients free of opiates 3, 6 and 12 months post-detox, respectively. Compliance with the naltrexone maintenance in abstinent patients was 66%, 68% and 30% at these time points. This NCOD protocol provides an efficient method of detoxifying opiate abusers with little patient discomfort or risk to health. Abstinence rates are better than those in comparable studies using other programmes.