Health, as defined by the World Health Organization, is a condition of “complete physical, mental and social wellness and not just the absence of illness and infirmity”. Different definitions have been applied over time for many different purposes. For example, it has been said that health is the sum total of the good health practices, which includes cleanliness, hygiene, self-respect, social support, and the like. The definition also mentions that good health depends on the person’s attitudes and values, and his ability to make choices for himself, and to choose the kind of health that he needs. Thus, in order to attain health, one must first be healthy spiritually and socially.

According to the third definition, health is a state of complete well being in which all three components of health are simultaneously present. The first component of this definition is the absence or the resolution of diseases, which could be psychological, physical or social. The second component is the control and prevention of diseases, which could be either physical or mental. The third component is the treatment and rehabilitation of patients, who have either been victims or beneficiaries of diseases. The term disease has various meanings, depending on the area of study and on the culture of the people using it.

Some diseases may be physical in nature and can be prevented and treated, while other diseases may not be curable and may require extensive medical intervention, either surgical or non-surgical. According to the first and second definitions, health is a state in which all the three components of health are necessarily present, although in varying degrees. The absence or resolution of diseases is not considered to be equivalent to health. Indeed, the absence or resolution of a physical disease may itself be an indication of a physical disorder or illness, whereas the absence or resolution of a mental or emotional disease may itself indicate a mental disorder or illness.