Sweating treatment (Swedana) is usually given after fat administration (oleation – Snehana) therapy. These two are administered as preparation to Panchakarma therapy. In some cases, Sweating treatment is administered as a standalone treatment for diseases of Vata and Kapha treatment. The 14th chapter of Charaka Samhita Sutrashana explains in dtail about sweating therapy.
A simile for the effect of fomentation therapy:
Now the different type of sweating therapy (fomentation) will be explained. If properly administered, diseases of Vata and kapha imbalance can surely be treated with fomentation. if administered after Snehakarma (oleation), fomentation brings Vata under control. It cleanses feces, urine and semen.
Even dry pieces of wood can be bent by oiling and heating. Similarly, Doshas can be balanced with oleation and fomentation. [3-5]
Extent of fomentation:
Sweating therapy – neither too hot nor too mild-combined with proper herbs and applied with taking into account – the diseases, the season, the individual patient and organ affected by the diseases, is very effective. 
Grades of fomentation:
If the disease is of serious type, if the season is very cold and if the body of the patient is quite strong, then very strong fomentation is prescribed,
If the diseases is mild, the season is moderately cold and the body is weak, mild fomentation is prescribed.
If all are of moderate nature, then moderate fomentation is prescribed.
In Vata – Kapha imbalance disorder, Snighda-Rooksha sweda is administered. – Oiling and drying type of sweating.
In Vata imbalance disorder, Snigdha sweda – oiling type of sweating is administered.
In Kapha imbalance disorder, Rooksha Sweda – dry type of sweating is administered. [7-8]
If the Vata is accumulated in Amashaya (stomach) then Rooksha sweda (dry fomentation) is preferred. This is because Amashaya is the site of Kapha. (read more – Kapha Dosha dominant body parts)
If the Vata is accumulated in Pakwashaya – intestines, then Snigdha Sweda (oily fomentation) is preferred.  Because Pakwashaya is dominated by Vata.
Body parts Contra-Indicated for fomentation:
Fomentation should be avoided over testicles, heart and eyes.
Even if it is very necessary to administer, it should be of mild type.
Over groins it should be moderate.
Fomentation on other parts of the body could be according to the individual needs.
Before sweating therapy, eyes should be covered with very clean cloths, a ball of wheat flour or leaves of Kamala (lotus) and Utpala (Nymphaea alba) or Palasha (Butea monosperma). Similarly Heart is to be covered with cool pearl necklaces, cool utensils, Lotuses, wet water or simply by the touch of cold hands. [11-12]
Signs of Ideal fomentation – Samyak Swinna Lakshana
Fomentation is to be administered until there is
Sheeta Shoola Vyuparama – complete recovery from coldness and pain,
Sthambha Gaurava Nigraha – relief from stiffness and heaviness of the body
Mardava – softness or tenderness of body parts.
After observing these signs, the sweating process should be stopped. 
Signs of excessive sweating treatment – Ati Sweda Lakshana
Aggravation of Pitta,
fainting, fatigue, excessive thirst, burning sensation, weakness of the voice and limbs – these symptoms of excessive sweating.
Such a person should be treated with summer season regimen (cooling therapies). Sweet, unctuous and cold principles should be used in treatment. [14-15]
Contra-Indications for fomentation: Swedaha Anarha / Aswedya
It is contra indicated in
Kashaya Madya Nitya – those who take excessive astringent foods and alcohol on a regular basis,
Garbhini – the pregnant woman,
Raktapitta – bleeding disorders, such as menorrhagia, nasal bleeding etc.
People with Pitta body type
diarrhea, people with excessive dryness,
chronic urinary disorders, diabetes,
Vidagdha-Bhrasta-Bradhna – inflammation and prolapsed of the rectum, burn injuries, toxic conditions, Alcoholism;
Those who are fatigued, unconscious,
very obese people, who are very thirsty, hungry,
who are suffering from anger and anxiety,
those suffering from jaundice, abdominal diseases, Vatarakta (gout), Timira (fainting);
those who are weak and dried up and whose Ojas has been reduced. [16-19]
Indications for sweating therapy:
Fomentation is useful for
Pratisyaya (coryza) – running nose,
Kasa – cough, cold,
Hikka – hiccup,
Shwasa – dyspnea, asthma,
Alaghava – heaviness of the body,
Karna, Manya Shira Shula – pain in the ear, neck and head,
Svarabheda – hoarseness of voice,
Galagraha – obstruction in the throat,
Ardita – facial paralysis,
Ekanga Sarvanga Pakshaghata – paralysis of one limb, whole body or half of the body,
Vinamaka – bending of the body,
Anaha, Vibandha – bloating, constipation,
Mutraghata – dysuria, urinary obstruction,
Vijrumbhaka – Pendiculation, excessive yawning,
Parshva Prushta Kati Kukshi sangraha – stiffness of sides, back, waists and abdomen,
Grudhrasi – sciatica,
Mutrakrichra – dysuria,
enragement of scrotum, malaise,
pain and stiffness of feet, knee, calf, oedema,
Khalli – spondylosis,
Ama – diseases due to impaired digestion and metabolism,
in chills and shivering,
affliction of the ankle joint by Vata (Vata Kantaka),
in contraction, extension or colic pain, stiffness, excessive heaviness, numbness an in diseases affecting the whole body.[20-24]
Pinda means bolus, in Pinda sweda, a bolus or paste is prepared and used as source of heat to induce sweating.
One should prepare a bolus for fomentation with Tila – Sesame (Sesamum indium), Masha – black gram, Kulattha – horse gram, sour preparations, ghee, oil, meat porridge, Payasa (milk preparations), and flesh- this is indicated for Vata imbalance disorders.
Faeces of cow, ass, camel, pig and horse along with the barley grains with chaff, sand, dust, stone dried cow-dung and iron powder in a bolus from is useful for fomentation in diseases of Kapha imbalance.
These very drugs may be used for Prastara Sveda (fomentation by a hot stone) depending upon the nature of diseases.[25-26]
The person should be well massaged. Then he is taken into a heated underground cellar, which is heated with charcoal, without smoke. This leads to comfortable sweating. 
Nadi means a tube. In Nadi Sweda, the steam is generated by boiling specific liquids in a pot. The pot is attached with a pipe and through pipe, the steam is directed towards the desired body part that requires sweating treatment.
For Vata disorders – The steam is generated by by boiling the flesh of domestic, marshy and aquatic animals, milk, head of goat, blood, bile and the flesh of middle part of pig, unctuous substances like castor seeds, sesame seeds and rice.
For Kapha disorders, the steam is generated by boiling leaves of Varuna (Ccrataeva religiosa Frorst), Amritaka – Giloya, Eranda – castor, Shigru (Moringa oleifera Lam), Mulaka – radish, Sarshapa – mustard, Vasa (Adhatada vasica, Vamsha (Bambusa arundinacea), Karanja (Pongamia pinnata), Arka – Calotropis gigantea, Ashmantaka (Ficus rumphii), Shobhanjana (seed of moringa), Saireya (Barleria prionitis Linn), Malati (Jasminus Grandiflorum), Surasa – Tulsi and Arjaka(Ocimum Gratissimum Linn).
For Vata-Kaphaja disorders, Nadi Sveda should be given by boiling Bhutika (Trachyspermum Ammi Spreague), Panchamula(roots of Aegle Marmelos Corr, Oroxylum indicum Vent, Gmelina arborea Linn Stereospermum Suaveolens DC. And Clerodendrum Phlomids Linn.f) added with wine. Dadhi mastu (Whey), cow urine and sour preparations. [29-30]
Material for tub fomentation:
The Kashaya (decoction) prepared using above-mentioned herbs are to be used in a big water-tub for fomentation. Wherever necessary, tub fomentation is also administered with ghee, milk or oils. 
Ingredients of Upanaha Sveda:
Upanaha means pack, bandage or poultice. Here, sweating is induced by making a pack / bandage of ingredients, heating it and bandaging the body parts with such hot packs. Poultice should be prepared with wheat chips, barley, mixed with acidic preparations, unctuous substance, yeast and salt, or with fragrant substance, yeast, Jivanti – Leptadenia reticulata, Dill (Shatapuspa), Linseed (Uma), Kushta (Saussurea lappa.G.B Clarke) mixed with Oil.
Leather with hair, devoid of bad smell and of hot potency animals (like antelops, etc. whose meat produces heat) is to be used as bandage. In cases of their non-availability, silk or woolen blanket may be used for this purpose.[35-37]
Period for Upanaha Sveda:
In order that the burning sensation may be prevented, normally, the bandage applied in the night should be removed in the morning and that applied during the day, should be removed in the evening: the duration of bandage may be prolonged in the winter.
Thirteen types of Swedana – fomentation:
The thirteen varieties of fomentation are Sankara, Prastara,Nadi, Pariseka, avagahana, Jentaka, Ashmaghana, Karshu, Kuti, Bhu, Kumbhika, Kupa and Holaka. They are described below.[39-40]
Sankara Sveda: Fomentation by means of bolus containing prescribed drugs with or without being wrapped with cloths.
Prastara Sveda: – bed fomentation
A bed is to be prepared of the size of the individual with corn, pulse and Pulaka (an inferior type of grain) or vesavara (a preparation of meat without bones together with long-pepper, black peppar, ginger, sugar-candy and ghee), Payasa (sweet milk preparation), Krushara (thick gruel), Utkarika (pudding), etc.
The bed is covered with silk, wool or with the leaves of Panchangula (Ricinus communis Linn),Urubuka (castor leaves) and Arka – Calotropis gigantea (Calotropis Gigantea R.Br . ex Ait) the individual, well-massaged all over the body, should be made to lie down over this bed. This process is known as Prastara Sveda.
Nadi Sveda – Tube fomentation:
Drugs for fomentation like roots, fruits, leaves, buds etc or flesh and head. Etc. of hot animals and birds are mixed with sour, salt or unctuous substances and urine, milk etc, depending on the nature of the disease. They are then heated in a mud pot, connected to a pipe. Pipe is made of Sareyaka or leaves of Vamsa (Bambusa Arundinacea R etz), Karanja – Indian Beech (bark / seed) – Pongamia pinnata(Pongama Pinnata Merr). Or Arka – Calotropis procera (Calotropis Gigantea R.Br.ex Ait) with its fore part having the shape of the trunk of an elephant. The pipe is required to be one Vyama (91.44cm) or half a Vyama (45.72cm) long with its proximal end, and one eighth of Vyama (11.43 cm) in the distal end. All the clefts in the pipe should be well covered with the leaves that alleviate Vata(like castor Leaves, dashamoola etc). The pipe should be curved in 2 or 3 places. The individual well massaged with unctuous substances that alleviate Vata should get this vapour through the curved pipe. Curvatures of the pipe help to lessen the intensity of vapour so as to avoid burning sensation. 
Parisheka – sprinkling –
Here, hot liquids are sprinkled over the body parts or whole body.
Pots with small holes at the bottom, bamboo pipes, Nala (Phragmites Karka Trin etc.) are to be filled up with luke warm decoctions (Kashaya) of roots, etc. of drugs which can cure Vata /Vata-Kapha diseases where Vata is predominant. Showers are then to be taken by an individual after he has been well-massaged with suitable unctuous substance and has been covered with cloth. 
Avagaha: tub fomentation
A tub should be filled up with Kashaya, milk, oil, ghee, meat juice or hot water that balances Vata and the patient should take bath in it. 
Jentaka Sveda – fomentation in a house-
One should construct a circular building facing the east or north side having a pond in front, at a suitable place. This should be done in the east or in the north direction. The building is to be erected on the southern or eastern bank of a water reservoir like small or big pond.
The level of the land should be plane and it should be situated at a distance of 7 – 8 Aratnis (320 cm to 365.76 cm) from the water reservoir.
The height and diameter of the building should be sixteen aratnis (731.52 cm) each.
The building should be uniformly circular, well plastered with mud and should have many windows.
A bench one Artani (45.72 cm) wide is then to be prepared all around the wall up to the door.
An oven of clay should be prepared in center of the room. Its diameter should be four Hastas (1.8 m) and height should be equal to that of an individual.
It should be circular in shape and should have many fine holes. The pillar-like oven should have a lid. This should be filled up with the fuel of Khadira – Black Catechu and Ashvakarna (Dipterocarpus alatus Roxb), etc. and should be ignited.
When the physician is sure that the fuel is burnt nicely and the smoke has completely disappeared and the room is heated by fire alone, and the hot temperature is achieved, he should ask the patient who is well-massaged with oils of Vata curing herbs and covered with a cloth, to enter the room.
The patient is asked to go over the bench and lie down on the cot (which is constructed along the circular wall from end to end). He should not leave the bench. He should move along the bench so as to come a circle in the room. When he feels that he is free from all obstructions, the sweat along with its sticking portion is completely drained out of the body, when his body is very light, and free from all obstructions, devoid of stiffness, numbness, pain, heaviness, then he should move towards the door following the bench. The patient should not sprinkle eyes with cold water, immediately after coming out of the room. After heat and exertions are relieved, he should take bath with Luke warm water after about three-fourth of an hour and then he can have meals. 
Ashmaghana Sveda – Stone Bed fomentation:
A compact slab of stone of the measurement of a man, is to be heated with the fuel of trees having Vata curing properties. All fire brands are then to be removed and the stone slab to be sprinkled with hot water. The slab is then should be covered with silk or woolen sheets. The person after being massaged, should be covered with cotton / silk should lie down on the slab. By so doing, he will be comfortably fomented. [47-49]
Karshu Sveda: – bed fomentation inside a room –
A thick-walled cottage, round in shape, should be constructed. It should neither be too high nor too wide. There should not be any window in it. The (inner wall of this) cottage should be plastered with drugs like Kushta – Saussurea lappa etc.
In the center of the cottage, there should be well-covered sheets prepared of cotton, silk, Kusha grass, blanket or Golaka (a variety of Woolen cloth). The bed should be surrounded with furnaces filled up with fire- brands. The person well-massaged should lie over this bed. Thus, he will get comfortably fomented. [52-54]
Bhu type fomentation should be carried out on the same principle as “Ashmaghana Sveda” on the floor (instead of lying down on a bed, here, the patient lies down on the floor). An auspicious area, which is free from excessive wind, should be selected for this purpose. 
Kumbhi Sveda :
A pitcher / pot is to be filled up with Kashaya of drugs that alleviate Vata and buried in earth upto one half or one-third part. Hot iron balls or stones should be put into the pitcher. A bed or seat covered with a thin sheet should be kept over it and the patient should either lie down or sit over it. Before administering this type of Sweda, the patient should undergo massage and his body should be covered with cloth. [56-58]
Kupa Sveda – well fomentation:
A well-like pit of the width of a bed and twice as deep as width should be dug out in an auspicious place which is not exposed to wind. Inner portion of this should be cleaned up. It should be filled with the dung of elephants, horses, cows, asses or camels and then ignited. A bed should then be placed over this well. The person well- massaged and well-covered, lying on this bed gets comfortably fomented.[59-60]
A heap of dung (of elephants, horses, cows, asses or camels) of the size of a bed is to be ignited. When it is well burnt has become smokeless, a bed covered with a thin sheet is to be kept over it. The patient with his body well-covered after massage should lie over it to get fomentation comfortably. [61-62]
The above are the thirteen types of fomentation involving the direct application of fire – Agni Sweda. 
Niragni sweda – Fomentation without fire:
The ten methods of fomentation without direct source of heat are called as Niragni Sweda. They are –
Vyayama – exercise,
Ushma Sadana – residing in a warm chamber,
Guru Pravarana – wearing of heavy clothing,
Kshuda – hunger,
Bahupana – excessive drinking,
Bhaya – fear,
Krodha – anger,
Upanaha – application of poultice,
Aha – wrestling and
Atapa – exposure to sunlight. 
Classification of fomentation techniques:
Agni Sweda – direct heat application
Niragni Sweda – without heat source
Ekanga Sweda – fomentation only to a particular body part
Sarvanga Sweda – fomentation to the whole body part.
Snigdha sweda – fomentation using oily and fat substances (in Vata disorders)
Rooksha sweda – fomentation using dry substances (In Kapha disorders) [65-66]
Pre- fomentation and post fomentation managements:
After the oleation therapy, the patient should be kept on wholesome diet. After fomentation, the patient should abstain from exercise on that day. 
Summing up the contents:-
The procedure for the effective administration of fomentation, patients for whom it is beneficial, different types of sweating techniques, signs and symptoms of proper, excess fomentation, drugs useful in fomentation, general principles guiding fomentation, thirteen types of fomentation involving the direct application of fire- the ten types without it – all these are described in this chapter on fomentation.[68-70]
Thus ends the fourteenth chapter on “fomentation “ of the Sutra section of Agnivesha’s work as redacted by Charaka