The word gunas commonly connotes thread but in its philosophical sense it means constituent quality. According to Samkhya philosophy the whole universe is based on the three gunas in different proportions .It is an analogy of three strands of rope twisted together. The three gunas are sattva (virtue, goodness), rajas (passion, activity), and tamas (darkness, dullness). Sattva is associated with virtues and qualities such as wisdom, joy, altruism, and brightness. A person with more of sattva has a positive or even orderly state of mind. Such a person is psychologically kind, calm, alert and thoughtful. Rajas is associated with greed, ambition, activity, and anger. It leads one to activity and is explained by the term Yogakshem. Yoga in the present context is acquiring something that one does not have. Kshem means losing something that one already has. Tamas is associated with idleness, ignorance, and delusion. A tamas quality also can imply that a person has a self-destructive or entropic state of mind. That person is constantly pursuing destructive activities. The soul must strive to detach itself from all three gunas. Everything in the universe is involved with the three gunas, which form the basis of the qualities and values of life. In all human beings one of the three gunas has superior strength and this is reflected in all they do and think.

In Classical literature (e.g. Mahabharata, Bhagavata Purana and Bhagavad Gita), a Guna is an attribute of the five elements (each with an associated organ) ether has sound (shabda) for its Guna (and the ear for its organ),air has tangibility and touch for its Gunas (and the skin for its organ),fire has shape or colour, tangibility, and sight for its Gunas (and the eye for its organ),water has flavour, shape, tangibility, and taste for its Gunas (and the tongue for its organ),earth has all preceding Gunas, plus its own peculiar Guna of smell (and the nose for its organ).

In Nyaya philosophy, twenty-four Gunas are enumerated as properties or characteristics of all created things rupa(shape, colour), rasa (savour), gandha(odour), sparsa(tangibility ), samkhya (number), parimana (dimension), prthaktva(severalty), samyoga(conjunction), aparatva(proximity ), gurutva( weight), vibhaga( disjunction), paratva( remoteness), dravatva( fluidity), sneha( viscidity), prayatna(effort), shabda( sound), buddhi or jnana(understanding or knowledge), sukha(pleasure), dukkha(pain), iccha(desire), dvesa(aversion),dharma( merit or virtue), adharma(demerit), samskara(the self-reproductive quality)

According to the ayurveda medicines and foods are sattivic ,rajasic or tamasic or a combination of these gunas .Sattvic foods are fresh juicy ,light ,nourishing ,sweet and tasty and give necessary energy to the body without taxing it .For example fresh fruits and vegetables that are easily digestible ,pure fruit juices ,fresh milk and butter,grains and nuts,honey,sprouted seeds ,cereals and wholemeal bread. .Rajasic foods are bitter,sour,salty,pungent ,hot and dry They over stimulate the body and excite the passions.For example sattvic foods that have been fried in oil ,cooked too much or eaten in excess are rajasic.These includes coffee and tea ,fish ,eggs salt and chocolate .These foods are also characterised by spices that are strongly exciting .Tamasic foods are dry ,old ,decaying and consume a large amount of energy while being digested . The body`s resistance to disease is destroyed and the mind filled with dark emotions, such as anger and greed. For example foods that have been strongly processed ,canned or frozen and are old ,stale or incompatible with each other .Meat ,vinegar ,liquor are especially tamasic. Overeating is also regarded as tamasic .Saints and seers can survive on sattvic foods .Householders that live in the world and haverto keep pace with its changes needs rajasic foods along with satavic foods .They ought to keep a balance between the foods try to avoid tamasic foods as much as possible.

According to the Bhagvad Gita those who can conquer the Gunas live in eternal happiness .At the same time conquering the Gunas frees one from birth old age ,disease and death.