28th chapter of Charaka explains how different types of foods undergo digestion, how they nourish different body tissues, how wholesome diet and regimen causes health and unwholesomeness causes disease and so on. The chapter name is Vividha Ashita Peeteeya Adhyaya
Digestion and nourishment
Digestion of food and nourishment of body tissues:
Antaragni (internal fire) empowers digestive fire to digest various types of food –
Ashita – eatables
Peeta – liquid foods
Leeda – linctus, jams,
Khadita – masticable foods.
Then the foods are taken to Dhatu level. (level of body tissues – blood, muscle, bone tissue etc). Here, the food is subjected to Dhatu agni – digestive process that converts particular part of food into the native Dhatu. There are seven Dhatu, so seven Dhatu agnis convert respective part of food into body tissue.
The food, thus digested causes
Upachaya – body nourishment, plumpness
Bala – strength and immunity
Varna – skin tone and complexion
Sukha – comfort, good mental health
Ayusha – improves life expectancy.
Thus all the body tissues get well nourished. 
How waste products of the body get support:
Nourishment of waste products
Food, after digestion takes two forms viz,
Prasada – the essence part, that is formed in the first stage. This is also called as ‘Rasa’
Kitta – the waste part. The waste part further nourishes
Sweda – sweat,
Mootra – urine
Pureesha – feces
Tridosha – Vata, Pitta and Kapha
Excreta of the ear, eye, nose, mouth, hair follicles, as well as genitals organs and also to
Kesha – hair of the head,
Shmashru – beard,
Loma – small hair of the body,
Nakha – nails etc.,
Nourishment of Dhatus
How the body tissues – Dhatu gets nourishment:
From the Rasa – essence part of food digestion, the successive dhatus –
Rudhira – blood
Mamsa – muscle
Meda – fat tissue
Asthi – bone tissue
Majja – contents inside bone, bone marrow
Shukra – reproductive system get nourished successively.
then all the sense organs, body joints get nourished.
Thus the essence part (Rasa (taste) and waste part (Kitta or Mala) of food nourishes the body tissues and body waste products respectively and thus the proper portions of tissues and waste products are maintained in balance, according to the size and shape of the body.
Due to certain causes, the tissue elements may get Kshaya (depletion) or Vruddhi (excessive increase). Similarly, even the waste products can undergo Kshaya or Vruddhi,the right amount of food, with correct opposing qualities of hot and cold, causes re-balancing of this increase / decrease. 
Relation of foods with body and Diseases
The pure as well as waste products (of digestion and metabolism) enter into the various channels of circulation (Srotas) and circulate though them. Each tissue (Dhatu) has its own channel (Srotas). These channels (Srotas) carrying specific nutrient material provide nourishment in required quantity to various Dhatus. Thus the body is the result of nourishment drawn (in fourfold manner) from eatables, beverages, linctuses, and masticates.
Diseases are also manifested in the body by the four types of foods (viz, eating, drinking, licking and masticating). Intake of wholesome and unwholesome food is the cause for health and disease respectively. 
Agnivesha inquired “Oh! Lord, people taking so called wholesome foods are found to suffer from diseases even though some of them are healthy. And a few people taking unwholesome food are found to be healthy. In view of this, how to draw the conclusion that health and diseases are conditioned by wholesome and unwholesome food respectively.
Cause for disease
Lord Atreya replied, “It is not that individuals accustomed to wholesome food suffer from diseases, due to the food that they are taking.
It is not only by taking wholesome food one can overcome all diseases.
Apart from unwholesome diet, there are other factors for the causation of diseases. They are –
Kaala Viparyaya – seasonal abnormality,
Prajnaparadha – intellectual blasphemy – knowingly committing mistakes
Shabda Sparsha Rupa Rasa (taste) Gandha Asatmya – unwholesome contents of sense faculties with their objects like sound, touch, vision, taste and smell. These factors may produce diseases even in individuals accustomed to wholesome food.
Due to certain factors, even unwholesome food does not produce diseases immediately. All unwholesome foods are not equally bad: all Doshas are not of equal strength, nor all bodies capable of resisting diseases equally.
An unwholesome food article – Apathya is harmful (or not) depending upon the
Desha – nature of the locality,
Kala – season / time
Samyoga – combination
Veerya (potency) and
Pramana – quantity.
So, an unwholesome diet becomes more unwholesome, if taken in wrong season, in wrong place, with bad food combination, in improper quantity.
The Doshas become more acute and difficult-to-cure if they are combined with each other, if they require mutually contradictory therapies (for example, Kapha needs hot treatment but if it is associated with Pitta, then, Pitta needs cold treatment) if they are deep seated, if chronic, if vitiated in body parts where life is situated and if they afflict the vital organs.
People with obese or emaciated body, or having loose muscle, blood and bone tissues or weak or nourished with unwholesome food or accustomed to the intake of less food or having feeble mind, are unable to resist diseases. On the other hand, individuals having opposite type of physical constitution are capable of resisting diseases.
The intake of unwholesome food, as well as the Doshas and physical constitution of above description gives rise to diseases of many types, viz mild or severe and acute or chronic. The Doshas, viz, Vata Pitta and Kapha give rise to various types of diseases depending upon the site of Dosha vitiation.
We shall now describe the various diseases which occurs in different sites (Dhatus) like Rasa due to the aggravation of the Doshas.
Rasa pradoshaja roga
Rasa Pradoshaja Roga – Diseases due to vitaiated Rasa Dhatu (the first essence part got after digestion process):
Following diseases are caused by the vitiation of Rasadhatu.
Ashraddha – Disinclination for food,
Aruchi – anorexia
Asya Vairasya – foul taste in mouth
Arasanjnata – lack of taste sensing capacity
Hrullasa – nausea,
Gaurava – heaviness
Tandra – drowsiness, fatigue
Angamarda – Malaise, bodyache
Jwara – fever
Tama – darkness in front of eyes
Pandutva – anemia, pale discolouration of skin
Srotasam rodha – obstruction of body channels
Klaibya – impotency
Saada – heaviness of body, as if the body is struck and cannot function.
Krushangata – emaciation, shrunken body parts
Nasho Agnehe – loss of digestion strength
Ayatha Kala Vali Palita – premature winkling of skin and graying of hairs. [9-10]
Rakta pradoshaja roga
Rakta Pradoshaja Vyadhis – Diseases due to vitiated Blood tissue:
Kushta – Skin diseases
Visarpa ( acute spreading diseases of the skin)
Pidaka – carbuncle, Pimples,
Raktapitta (a diseases characterized by bleeding from different parts of the body),
Asrugdhara – menorrhagia, heavy periods
Guda Medhra Paka – inflammation and suppuration in rectum and penis
Asya Paka – mouth ulcers,
Pleeha – Disease of the spleen, Splenomegaly
Gulma – Tumors of the abdomen
Vidradhi – Abscess
Neelika – blue moles,
Kaamala – Jaundice,
Piplava (portwine mark),
Tilakaalaka (black mole),
Dadru – ringworm ,
Charmadala- dermatitis, skin tags
Shvitra – leucoderma,
Pama – papules,
Kotha (urticaria) and
Asra Mandala – red circular patches. [11-12]
Mamsa pradoshaja roga
Mamsa Pradoshaja Vikara – Diseases the causes by vitiated Muscle tissue:
Adhimamsa – Granuloma,
Arbuda – Myoma
Keela – Piles,
Gala Shalooka – Uvulitis,
Gala shundika – tonsillitis,
Pootimamsa – Sloughing of flesh,
Alaji – boils,
Ganda – goiter,
Gandamala – cervical adenitis
Upajihvika – inflammation of epiglottis. [13-14]
Meda pradoshaja roga
Meda Pradoshaja Vikara – Diseases due to vitiation of fat tissue
Asthi pradoshaja roga
Asthi Pradoshaja Vikara – Diseases caused by vitiated bone tissue:
Adhyasthi – Hypertrophy of the bones
Adhi danta – excess teeth,
Dantabheda – cracking sensation in the teeth
Asthibheda, Shoola – crackling sensation and pain in bone,
Vivarnata – discoloration of hair
Deformity of hair of head, body hairs, nail as well as beard.
Majja pradoshaja roga
Majja Pradoshaja Vikara – Diseases due to vitiated bone marrow tissue:
Parva Ruk – Pain in small joints
Bhrama – Delusion, Dizziness
Murcha – fainting, loss of consciousness
Tamo Darshana – seeing darkness in front of eyes
Manifestation of deep-seated abscesses in joints 
Shukra pradoshaja roga
Shukra Pradoshaja Vikara – Diseases due to vitiated Semen / reproductory system:
Due to the vitiation of Shukra or semen the individual suffers from
Klaibya – impotent
Aharshana – lack of erection and enjoyment in sex
His progeny, if any, will be sick, sterile, short lived and disfigured.
Either there is no conception or there will be abortion or miscarriage. Thus the vitiation of Shukra (semen) brings misery to the couple and progeny.[18-19]
Affection of sense organs
Sense organs are either totally or partially destroyed when Doshas get vitiated and lodge in them. 
Affection of tendons and ligaments
Doshas when vitiated in tendons (Snayu), vessels (Sira) and ligaments (Kandara), they cause
Stambha – stiffness
Samkocha – contraction,
Khalli – neuralgia of the upper and lower extremities,
Granthi – tumor, fibroid
Sphurana – throbbing sensation and
Supti – numbness.
Vitiation of waste products
When Doshas get vitiated in waste products, they cause
Bheda – dislodgement of stool,
Shoshana – drying up,
Pradushana – impairment
Sanga – absolute retention or
Utsarga – excessive elimination of these waste products
Treatment principle for management of diseases caused by Errors in Food:
Diseases enumerated for Dhatu (tissues), waste products(mala), ligaments, tendons etc are caused by the improper intake of food comprising eatables, beverages, lockable and masticables. One should always take wholesome food with a view to preventing the occurrence of such diseases.
Rasa Dhatu treatment
For diseases caused by bad foods, affecting Rasa Dhatu, Langhana treatment should be adopted. (such as fasting, exercise etc.. which brings about lightness to the body).
Rakta Dhatu treatment
Treatment of diseases caused by the vitiation of Rakta is described in the 24th chapter of Sutrasthana – Vidhi Shoniteeya Adhyaya
Mamsa Dhatu treatment
For muscle tissue disorders,
Samshuddhi – Panchakarma purification treatment
Shastrakarma – surgery
Ksharakarma – application of Kshara (water insoluble ash of herbs)
Agnikarma – cautery treatment
Medo Dhatu treatment
The fat tissue disorder treatment is explained 21st chapter of Sutrasthana – Ashtau Ninditeeya Adhyaya
Asthi Dhatu treatment
For diseases of bone tissue,
Especially Basti (enema) with milk, ghee and bitter herbs is useful.
Majja and Shukra Dhatu treatment
Majja (marrow) and Shukra Dhatu (reproductive system) treatment:
Majja and Shukra Dhatu diseases are treated with diets of sweet and bitter tastes, sexual intercourse, exercise and timely elimination of Doshas (Panchakarma) in proper quantity.
For diseases of sensory organs
The treatment will be explained in detail in26th chapter of Chikitasathana (the sensation on the treatment of diseases). Treatment of diseases of ligaments etc. will be described in the chapter 28th of Cikitsathana – Trimarmeeya Chikitsa Adhyaya.
Treatment of diseases of waste products
Treatment of diseases of waste products, the line of treatment is already explained in 7th chapter of Sutrasthana – Na Vegan Dharaneeya Adhyaya [23-30]
Movement of Doshas
How Doshas move from gastro intestinal tract to limbs?
Due to Vyayama – exercise
Ushmana – excess heat, acuteness of the digestion, intake of excessive hot and spicy food,
Teekshna – intake of foods having piercing and strong nature
non-observation of wholesome regimen and
By the force and pressure of Vata,
the vitiated Doshas from alimentary tract spread to the periphery – limbs, muscles, bones etc.
In the absence of any exciting cause, the vitiated Doshas at times remain in dormant stage till they meet with the causative factors at appropriate time, place for the manifestation of their effects.[31-32]
Traction of Doshas from periphery to the alimentary tract:
Vruddhi – further aggravation,
Vishyandana – due to liquefication / increase in fluidity,
Paaka – due to suppuration,
removal of the obstructions in the channel of circulation (Srotas) and
the vitiated Doshas leave the periphery and come to the alimentary tract. 
In order to prevent the manifested diseases and to cure the manifested ones, an individual desirous of happiness, should follow the regimen prescribed in this text.
All the mental and physical activities of all the living beings is to achieve Sukha – happiness. A wise man follows the proper path. An ignorant one takes the unwholesome path. [34-35]
Importance of wholesome regimen
The wise person observes wholesome regimen, after proper examination. The ignorant person, with his mind covered with Rajas (attraction) and Tamas (illusion) run after apparently pleasing regimen.
How a person can avoid disease?
The wise man is endowed with
Shruta – sound knowledge
Buddhi – intellect
Smruti – memory,
Daksha – skill, discipline
Dhruti – good retention power
Hita Nishevana – ability to stick to wholesome regimen,
Vak Vishuddhi – clarity in speech
Shama – tranquility and
Dhairya – courage
Ignorant individuals being shrouded with illusion (Tamas) and Rajas (attraction) are deprived of those virtues and therefore, succumb to various disorders of body and mind. [36-38]
Consequence of ignorance
Prajnaparadha – intellectual blasphemy, knowingly doing the wrong things,
Ahita Indriyartha Sannikarsha – the ignorant indulges in unwholesome gratification of five senses,
Vega Dharana – suppression of natural urges,
Saahasa – straining beyond one’s capacity and|
adoption of such of the regime which yield only temporary pleasure. But the wise do not indulge in them because of their clarity of vision.[39-40]
Selection of food
The body is constituted of food hence one should take wholesome food only, after careful examination and should not indulge in unwholesome ones out of greed or ignorance.
Observation of eight factors
There are eight factors (described in Vimana Sthana 1st chapter, in future) to be considered in dietetics. They are responsible for causing happiness or misery. These factors are to be examined before taking any food.
Need to observe wholesome rules
The wise who always avoid the intake of unwholesome food are held in high esteem by saints. However, there are certain diseases which no one can avoid and in such events the wise need not worry. [43-44]
Summing up the contents:-
How food causes health and disease,
wholesome and unwholesome foods, being responsible for happiness and misery respectively, individuals who have immunity from and susceptibility to the various psychosomatic diseases, various diseases specific to each of the Dhatus,(tissue elements), therapies for their cure, the method by which Doshas get vitiated and come to the periphery from the alimentary tract and vice versa, specific characteristics of wise and ignorant individuals, regime useful for healthy individuals as well as patients all these are described in this chapter – Vividha Ashita Peeteeya Adhyaya
Thus ends the 28of Charaka Samhita Sutrasthana of Agnivesha’s work as redacted by Charaka.