Don’t stand between a woman and that leopard-print purse she’s eyeing at the mall.

She may be premenstrual, and it could get ugly. A new study in the U.K. has found that in the 10 days before their period, women may be under the influence of intense and powerful hormonal urges to shop.

Professor Karen Pine from the University of Hertfordshire presented her theory to the British Psychological Society meeting in Brighton.

Her psychological study involved asking 443 women about their spending habits. She found that women in the luteal, or late, phase of their menstrual cycle were more likely to overspend in the shops. Many of them felt remorse later.

“Spending was less controlled, more impulsive and more excessive for women in the luteal phase,” says Pine, explaining that it may be a reaction to intense emotions.

Women may also be “feeling stressed or depressed and are more likely to go shopping to cheer themselves up,” she says.

Call it retail therapy.

Another force that may be at work is that women with premenstrual symptoms are buying things to make themselves feel more attractive — especially when they are fertile and ovulating, about 14 days before they get their period.

Metro’s advice: Just stay out of the way and say, “That looks really good on you.”