According to new research a hormone that relaxes women during childbirth and breastfeeding has other uses.
It seems a small squirt of oxytocin lowered stress levels in both men and women who were quarrelling.
Oxytocin, has previously been linked with the ability to maintain healthy interpersonal relationships and healthy psychological boundaries with other people.
Beate Ditzen, now a psychologist at Emory University in Atlanta, says the results suggest the drug could be used to help battle stress and, possibly, reduce conflict.
Ditzen and colleagues at the University of Fribourg tested 50 heterosexual couples, asking them to discuss a subject that they often disagreed about.
Half the couples first got a nasal spray of a medical preparation of oxytocin and half got a dummy spray and the couples were then encouraged to fight out their differences while being videotaped.
Ditzen says the hormone appears to cut stress during tense social situations or conflict and supports work done with rodents, as well as in primates such as monkeys, which suggests that oxytocin affects sexual relationships among animals.
Ditzen says the couples who received oxytocin appeared better able to express their emotions, both negative and positive and more openly, than those who received a placebo.
The researchers suggest that oxytocin has a positive effect but advise caution about reaching final conclusions until all the data is analyzed.