There have been so many misperceptions and prejudices against mental illness in our society. The wrong perception and prejudice against mental illness infringe on basic human right to receive proper medical care. Thoughts such as 'mental illness is rare', 'it is incurable', or 'psychiatric patients are weird, violent and harmful to others' are typical stereotypes of mistaken beliefs about mental illness. Scientific studies conducted throughout the world provide the opposite of these views. To reduce misunderstanding and stigma of mental illness, it is important to lead the public to recognize the mental illness is a disease of the brain to be treated, and that it can be treated effectively. To achieve this aim, proactive promotion by government and non-government organizations including medical professionals is required. In addition, vigorous scientific investigations should continue to delineate the pathophysiology of mental illness and establish effective treatment thereof.