This article is the second of two describing the impact of the Mental Capacity Act on the practice of intensive care medicine in the UK. This article concentrates on the impact on clinical research. Intrusive research in incapacitated patients that does not involve trials of medicines or non-identifiable data is covered by the Act. Research must have Ethics Committee approval and must have some chance of benefiting the research subject or provide information about the disease without causing risk to the patient or being unduly invasive or restricting the patient's freedom. It is the responsibility of those engaged in clinical research to be aware of the requirements of the Act and to interpret and implement it appropriately.
