Ayurveda is a medical system that deals not only with body but with the mind and soul as well. According to ayurveda, most diseases connected with the psychophysiologic and pathologic changes in the body are caused by imbalance in different doshas (ie,bodily doshas viz vata, pitta, and kapha; and manas doshas viz satva , rajas ,tamas).So in ayurveda for healthy person equaninimity , composite state of equilibrium (samya)and cheerfulness (prasannta ) are the primary considerations .
Ayurvedic Definition of Health
Sam dosha, samagni, samdhatu malakriyah
Prasannatma, indriyas manaha swasthya ityabhidheeyate”
This definition of health was given by acharya Sushruta He described the features of a healthy person in the above quote..
so in ayurveda health is state of balance or equilibrium of doshas (regulatory physiological entities such as vata , pitta , kapha ),agni ( entire metabolic processes ). dhatus (bodily tissues or structural entities such as rasa , rakta etc ) and malas (excretory entities such as urine , faeces , sweat) proper functioning i.e excretion in normal state along with sensorial , mental , social and spiritual wellbeing. So optimal health is attained when there is perfect harmony between body mind and soul .Any disturbance in this equilibrium due to internal or external factors leads to diseases . When any of them is distutbed it is state of disease which means hinderance in acquiring the four Purusharthas of life i.e., dharma, artha, kama, moksha. And the main aim of Ayurvedic treatment is to keep all in balance along with constant pleasant or cheerful state of mind and soul too.

According to Acharya Charak diseases are due to imbalance of dhatus as mentioned below :
balance Dhatus.

Disease is distribution or imbalance in Dhatus and health is balance between them and health is defined as Sukh(happiness) and disease as Dukha (sorrow).
Main causes of imbalance in our biological functions are from the overuse, underuse and mis-use of the five sense organs,overnourishment or undernourishment or wrong choices of food ,improper conduct or behaviour and not understanding our relationship to nature . These are the basic causes that appear on the gross level, which gradually manifest into what we name specific disease conditions.
Ayurveda is the perfect solution for all our health issues. Not only does it help people understand themselves and their needs, but it also provides detailed guidelines on diet, lifestyle,code of good conduct , exercise regimens, seasonal regimens, sleep patterns and much more. But above all, Ayurveda teaches us to live in harmony within our society, with nature and with the universe at large, without disturbing the delicate natural balance.Ayurveda helps us in our endeavor to achieve optimal health and real happiness not only at body level but at mind and spiritual level also.