If you have a bully in the workplace, it is going to have a negative impact on productivity and employee morale.
As a leader, if you have a bully in the workplace you have to address it promptly and directly. Nobody has the right to intimidate another person. Even if you are the boss, you have no right to damage the self-esteem of another person. You have to stay on top of the situation until you see the bully has changed or has been terminated.
If you are the one who has been targeted by a bully, you need to either report the situation or leave the organization. If the bully is your supervisor, continue to do your best work while you look for another job.
If you are aware of a bullying situation that you are not involved in, you have an obligation to report it. Human Resources will want to resolve the situation, but may not be aware of what is happening.