Should doctors wear white coats? Most patients, especially older ones, would apparently rather see doctors wear white coats as a way of identifying who they are. Most doctors, on the other hand, perceive them as an infection risk and find them uncomfortable (Postgraduate Medical Journal 2004;80: 284-6). Minerva wonders if the infection risk would seem as great if coats were exchanged for clean ones every day.

Let them eat yoghurt. Graft versus host disease after transplantation results not only from a reaction between the donor and recipient cells, but also from triggers such as cytokines, which are produced in response to bacteria. To reduce the risk of the disease, many transplant units use gut decontamination regimens. But one team tried yoghurt containing lactobacillus in mice models and found that the outcome was improved and graft versus host disease reduced in the yoghurt fed mice compared with mice receiving antibiotics and control mice (Blood 2004;103: 4365-7).

Injecting knees with intra-articular saline after arthroscopy seems to produce good pain relief. Not only that, but a randomised double blind study showed that injecting 1 ml of saline was just as effective as injecting 10 ml ( Anesthesia and Analgesia 2004;98: 1546-51). The authors suggest the finding of such a major placebo effect may …