If you have ever promoted one of your employees to a manager, you may have unwittingly contributed to a corporate cancer that will destroy your startup.

How so? Your new manager may have won that promotion through a kiss-up-kick-down strategy--that's the practice of flattering those above you in the organization while sabotaging your peers and abusing your subordinates.

What's so bad about kiss-up-kick-down? It should be obvious but it's so common that I am confident that its costs to your company must be described.

The single most important one is that it takes the money and time you invested in hiring and training talented people and flushes it down the tubes.

How so? Talented people--especially with the improving job market--will not put up with being sabotaged by their peers and abused by their managers.

Instead, talent will bolt your company after their boss falsely takes credit for their best ideas while blames them for the boss's mistakes.

Similarly, an employee working on a project team with a kiss-up-kick-down type will become infuriated when that peer does not share with them a crucial piece of information--embarrassing him when he presents the project in front of his boss.

If you don't stop such people from gaining a foothold on your company's management ladder, they will hire and promote more people like themselves and you will soon find your company's talent heading for the exits.

And you may be responsible for rewarding this nasty--and too often effective--practice. After all, you might have gotten to where you are by being a kiss-up-kick-down type. If so, your company would be better off if you change your behavior.

Or you might be nave and easily swayed by an employee who apes what you wear, what you do in your free time, what you drive, and the way you talk while laughing at all your jokes and praising all your memos.

If you are nave, here are four things you can do to make sure you don't allow this cancer to kill your startup.

1. Don't promote anyone to manager without a 360 degree review.

Talk to everyone at your company who has worked with the individual. This includes administrative staff, peers, direct reports, customers, suppliers, and their current managers. Check with their former employers as well.

If the managers think this person is delightful but all the other people you talk with describe tales of treachery and deception, you must not promote this person.

Instead, you ought to fire him.

2. Create a culture that rewards individual respect--regardless of title.

If such a person was able to get hired at your company, there's a good chance that your culture does not place enough emphasis on respect for each individual.

Put this value into the mix you use to hire and reward employees. And make sure people know how strongly you value individual respect by telling stories to your people about why it's good for your company.

When you interview potential employees, make sure that they can show how well they treat people who have less power than they do. And check up on these stories by talking to the people they claim to have helped.

3. Encourage people to report mistreatment of subordinates and peers.

If people are being mistreated, this means that someone in your company is stealing from you. Do you allow your employees to take home your inventory at night and pocket half the money your customers pay you?

If not, why should you let some of your employees abuse others? After all, you are paying their salaries and benefits and you're training them and putting them in charge of important relationships with customers and suppliers.

Why shouldn't you have control systems that protect these valuable assets and notify you if they are being abused?

And once you put such systems in place, make sure you identify the culprit, verify the reports, and if you are confident that they are abusing people in your company, show them the door.

4. Set a great example for your organization.

You have tremendous power to lead since your people are inclined to observe how leaders behave and act accordingly.

You should treat everyone with respect. If you are abusive to your administrative assistant or your managers, they will view it as a license to mistreat their peers and their direct reports.

If you care about your people and give them opportunities to make progress in the organization, they will do the same for their people.

To do otherwise is to waste one of your organization's most valuable assets--and to admit a cancer that can quickly replicate and destroy what you've built.