Emotions and passions triggered by the first flushes of a love affair are as effective a pain-killer as any drug, new American research reveals.

For the study, fifteen male and female U.S. college students, all in the early stages of passionate love affairs, were shown images of their partners. At the same time, a computer-controlled heat probe delivered a mild dose of pain to the palm of their hands.

Meanwhile, their brain waves — which reflect pain triggers — were monitored.

The Stanford University Medical Center study found that feelings of love were helpful in relieving the heat-probe pain.

Focusing on an image of an attractive friend or acquaintance failed to have the same effect, explained Dr. Sean Mackey. “We are beginning to tease apart some of these rewards systems in the brain and how they influence pain,” he added.