For diseases such as typhoid and pneumonia, yoga should not be used, but this is the only limitation. Yoga is for chronic diseases like diabetes, asthma, and for constitutional diseases. In these cases one can use it safely. For diseases that pertain to an individual's behaviour, thinking, temperament, character, responsiveness and sensitivity, there is nothing better than yoga.
If an individual is suffering from terrible anger, or has an inferiority complex, or too many wrong notions about himself, there is nothing better than yoga. It creates a medium for self-correction. Many of the problems which are considered inborn are according to yoga physiological in nature.
Anger is intrinsically connected with the adrenal secretion and which again is intrinsically connected with coronary excitements. When one is angry there is excitement of the heart, and therefore, the adrenal secretions have to be balanced. They can be balanced by the practice of shashankasana, hare pose, for a period of time up to half an hour.
If there is overstimulation or understimulation of the adrenal gland, there could be a lot of anger. One could be ready with the revolver to shoot at anyone. Or perhaps, a person could be so passive that even if he is slapped on one cheek he would say, "Alright, the other cheek is ready."
Similarly, the understimulation or overstimulation of the thyroids could make a person emotionally hypersensitive or make him kill his emotions.
We recognize the psychological status of emotions such as love and hatred, but at the same time we know that they have a physiological bearing. Anger, love or compassion are not only psychological, they have a physiological base.