Environment effects were not due to factors shared by family members, and they were related to smoking and stress in men and use of analgesics in women.

"That makes these studies somewhat alarming as I doubt that anyone would have suspected that common painkillers would have these effects, " he said.

Results This practice achieved favorable effect in patients' usage of analgetic , time of breaking wind, complications post-operation and days of hospitalization.

Endorphins, the body's natural painkillers, also play a key role in long-term relationships.

They were then told they were being given a painkiller and the score went down to 39.