Complementary medicine continues to increase in popularity in the general community. As a result it is likely that requests for the administration of complementary medicine to intensive care patients will be more frequent in the future. It is therefore prudent for intensive care clinicians to address this issue and develop an approach that is consistent. Complementary medicine has not been subjected to well conducted trials to determine its efficacy and risks. Consequently decisions about its use cannot be based on risk/benefit analyses and genuine informed consent cannot be achieved. Therefore complementary medicine should not be incorporated into intensive care practice. Strict adherence to a policy of negating requests for administration of complementary medicine in intensive care patients may result in significant conflicts between intensive care clinicians, patients and families. On occasions the patient or family may insist on the use of complementary medicine and it may be seen as important to their psychological wellbeing to accede to the request. The intensive care clinician is still legally responsible for any treatment administered to the patient, even if it is against medical advice. Nevertheless if there is no demonstrable risk to the patient, complementary medicine can be administered following appropriate counselling and documentation. This review addresses the legal and ethical difficulties that may arise and an approach that may be followed when requests are made for complementary medicine in intensive care patients.