The National Institute for Health and Clinical Excellence (NICE) is acknowledged as a world leader in its field, yet the prevailing media image of NICE is as a controversial mechanism for denying patients expensive new drugs. Teresa Poole looks at how NICE appraises new and existing drugs through clinical and economic evidence and looks at the impact of those appraisals, including difficulties with implementation of the recommendations. The briefing assesses recent policy proposals to address the system's perceived shortcomings, including speeding up appraisals, setting a suitable threshold for cost-effectiveness and overcoming the problem of 'postcode prescribing', where there are significant geographical disparities in the availability of individual drugs not covered by NICE guidance. [Introduction]