Four series of duodenal ulcer patients presenting with pain have been treated with two types of placebos (intramuscular injections or tablets) by 4 different physicians while a fifth group of patients did not receive any treatment. Patients noted the number of days with pain since the beginning of the test by themselves. All patients treated with placebo presented with a significantly shorter duration of pain than untreated patients. There was a significant difference between the actions of the different physicians on the duration of pain. This suggests that some, until now unprecised, character(s) of the physician plays an important part in the relief of duodenal ulcer pain.