When a colleague is mean to you, it can be hard to know how to respond. Some people are tempted to let aggressive behaviour slide in the hopes that the person will stop. Others find themselves fighting back.

"When it comes to bad behaviour at work, there's a broad spectrum," with outright bullies on one end and people who are simply rude on the other, says Michele Woodward, an executive coach and host of Harvard Business Review's recent webinar, Bullies, Jerks, and Other Annoyances: Identify and Defuse the Difficult People at Work.

You may not know which end of the spectrum you're dealing with until you actually address the behaviour. If it's a bully, it can be difficult – if not impossible - to get the person to change, says Gary Namie, the founder of the Workplace Bullying Institute and author of The Bully at Work. But in most cases, you can – and should – take action.

Here are some tactics to consider when dealing with an aggressive colleague:

Understand why. The first step is to understand what's causing the behaviour. Research from Nathanael Fast, an assistant professor at the University of Southern California's Marshall School of Business, proves a commonly held idea: People act out when their ego is threatened. So it may help to stroke the aggressor's ego. Even a small gesture, such as ending an email with "Thanks so much for your help" or complimenting the person on something you genuinely admire, can help.

Look at what you're doing. These situations also require introspection. "It's very easy to say, 'Oh, that person is a jerk,' " Woodward says. But perhaps you work in a highly competitive culture or one that doesn't prioritise politeness. Consider whether you might be misinterpreting the behaviour or overreacting to it or whether you've unknowingly contributed to the problem. Have you in any way caused the person to feel threatened or to see you as disloyal?

Stand up for yourself. Don't be afraid to call out the bad behaviour when it happens. "I believe very strongly in making immediate corrections," says Woodward. "If someone calls you 'Honey' in a meeting, say right then: 'I don't like being called that. Please use my name,' " she says.

Enlist help. "Everybody should have alliances at work – peers and people above and below, who can be your advocates and champions," says Woodward. Talk to those supporters and see what they can do to help, whether it's simply confirming your perspective or speaking on your behalf. Of course, you may need to escalate the situation to someone more senior or to HR. But before that, "you owe it to the relationship to try to solve it informally," says Woodward.

Demonstrate the cost to the business. If you do need to take formal action, start with your boss (assuming he isn't the aggressor). But you may need to take the issue higher up the hierarchy. When you have someone's ear, Namie recommends, focusing the conversation on how the person's behaviour is hurting the business.

Know the limitations. When none of the above works you have to consider: Is this uncivil, mean behaviour or am I being bullied? If you are in an abusive situation (not just a tough one), Namie and Woodward agree that chances of change are low. If you're in an abusive situation at work, the most tenable solution may be to leave – if that's a possibility. Amy Gallo is a contributing editor at Harvard Business Review. In association with Harvard Business Review