A spritz up the nose may help restore happiness to fighting couples living together, according to scientists studying the effects of a nasal spray containing the hormone oxytocin.

Scientists found that a sniff of the "cuddle hormone" oxytocin makes women calmer and friendlier and men more sensitive and positive during argument.

A new study, published in the journal Social Cognitive and Affective Neuroscience, found that couples who used the oxytocin nasal spray before going into a contentious discussion about their relationship behaved more positively than couples who hadn't.

Researchers at Zurich University studied 47 couples between the ages of 20 to 50 who were either married or had lived with each other for at least a year.

Hailed as the "love drug," oxytocin is a hormone that is naturally made in the hypothalamus region of the brain and is involved in sex, sexual attraction, trust and confidence.

Previous research has found that the hormone is released when a woman is in labor to dilate the cervix, boost contractions, trigger lactation and to help enhance bonding between mother and child.

Researchers studied the effects on stress and the activity of the autonomic nervous system, a part of the peripheral nervous system that automatically regulates organs of the body. Previous research found that this part of the nervous system is more active during conflicts between couples, leading to higher heart rate and blood pressure.

The couples were asked to choose a topic to discuss which caused conflict in their relationship before administering five puffs of either oxytocin or a placebo spray. 

Forty-five minutes later, researchers left each of the couples alone in a room and filmed participants discussing the contentious debate.

At various times during the experiment researchers collected saliva swabs from participants to check for compounds showing the nervous system activity of the participants.

The study results found that compared to those who had sniffed the placebo, women who had the oxytocin spray showed a drop in nervous system activity, whereas in men the spray increased nervous system activity.

While the spray appeared to make the men display greater positive behavior, the women became friendlier.

Psychologists say that when couples get into an argument, women tend to show demanding behavior more frequently and men tend to withdraw, and the latest findings suggest that the "love drug" appeared to have reversed the gender behavior and "driven quiescence in women and social salience and approach behavior in men," the authors wrote in the study.

Nottingham University professor Kavita Vedhara told The Independent that the results from the latest study showed that oxytocin reduced women's "emotional and physiological arousal following verbal conflict" while the opposite happens to men.

"We are much clearer about the biological role of oxytocin in women, but these data suggest it could have significant effects in men. What they have shown is that oxytocin appears to reduce women's emotional and physiological arousal following verbal conflict, but that the drug has the opposite effect on men, increasing both their emotional and physiological arousal. It is not clear if the increased emotion in men was always positive, but it was certainly associated with more positive behaviors during the conflict situation," Vedhara said, according to the UK-based newspaper.

Scientists will now look further into the possible benefits of the hormone oxytocin on bickering couples.

"It is possible that the effect simply produced short-term changes in how couples interact with each other," said Vedhara. "This might help to take the heat out of an argument. But whether it helps to resolve the issues that lead to the arguments is not clear."

Previously, scientists at the University of California also found that the "love drug" nasal spray may also help to enhance libido in men. They found that a married man who had sniffed the spray twice a day saw a dramatic improvement in his sexual performance.