Psychedelic drugs have captured the attention of health-care providers and patients alike for their increasingly apparent potential to effect long-lasting improvements in the mental health of people suffering from conditions such as treatment-resistant depression. Controlled trials to arrive at objective results are limited by current regulations, but evidence is mounting to suggest a place for psychedelics in the pharmacopeia for emotional and mental disorders. Experts will review the evidence to date and assess the potential of psychedelics in the care of many patients whose mental suffering is resistant to treatment.