It is 10 years since the CONSENSUS I study showed that ACE inhibitors improved mortality in heart failure. This finding has been confirmed in numerous trials, for example SOLVD, SAVE. Indeed, in the intervening 10 years, many other potential therapies have been examined in mortality trials, but so far no other therapy has had as good effect on mortality as ACE inhibitors. The other therapies which have been examined are digoxin, amlodipine, beta-blockers, amiodarone, etc. Despite ACE inhibitors being a very effective therapy for heart failure, there is still remarkable under-use of them in clinical practice. The reason for this needs to be explained further, but fear of hypothermia and renal dysfunction appear to be major factors.