Admission to proof from unsatisfactory drug-development programmes advances the whole scientific procedure explains Enrica Alteri and Lorenzo Guizzaro. Self-help and business books are complete with guidance for knowledge from failures. The biomedical community must do just that if it is to ease the trouble from stubborn conditions such as Alzheimer’s disease. It can take 20 years or more to get a drug to market, from testing compound in animals to running late-stage (phase III) clinical trials in thousands of subjects. More than 80% of drugs that are tested in humans fail to show safety and efficacy.