The effect of an aerosol containing 5alpha-androst-16-en-3-one on oxytocin release in the sow was studied. The snouts of six estrous sows were sprayed with the aerosol for 2 sec. Blood samples were collected through indwelling vena cava canulas. The aerosol released oxytocin in all the sows tested. Maximum values, ranging from 24 to 101 pg oxytocin/ml plasma were recorded within 8 min of the treatment. A possible positive effect of the pheromonal stimulation on pigs' fertility is hypothesized.