The failure of aromatherapy? The effect of pleasant and unpleasant odour on pain perception.

Sixty healthy men and women experienced experimentally-induced pain during exposure to either a pleasant odour (lemon), an unpleasant odour (machine oil) or no odour.
Participants reported the degree of pain they experienced at five minute intervals for 15 minutes. Individuals exposed to both odours reported significantly greater pain than did the participants in the control condition at five minutes. At 15 minutes, individuals exposed to the unpleasant odour experienced greater pain than did the control group. The results suggest that exposure to odour is not beneficial to those seeking pain relief. Rather, its perception is associated with greater pain than is no odour.