विशेषतस्तु कुष्ठज्वरमेहोर्ध्वरक्तपित्तभगन्दरोदरार्शोब्रधप्लीहगुल्मार्बुदगलगण्डग्रन्थिविसूचिकालसकमूत्राघातक्रिमिकोष्ठविसर्प– पाण्डुरोगशिरःपार्श्वशूलोदावर्तनेत्रास्यदाहहृद्रोगव्यङ्गनीलिकानेत्रनासिकास्यस्रवणहलीमकश्वासकासकामला– पच्यपस्मारोन्मादवातरक्तयोनिरेतोदोषतैमिर्यारोचकाविपाकच्छर्दिश्वयथूदरविस्फोटकादयः पित्तव्याधयो विशेषेण महारोगाध्यायोक्ताश्च; एतेषु हि विरेचनं प्रधानतममित्युक्तमग्न्युपशमेऽग्निगृहवत्|| (Cha. Si. 2/13)

According to Ācārya Caraka, virecana is indicated in kuṣṭha, jvara, meha, ūrdhvaga raktapitta, bhagandara, udara, arśas, bradhna, plīhā, gulma, arbuda, galagaṇḍa, granthi, viṣūcikā, alasaka, mūtrāghāta, krimi koṣṭha, viṣarpa, pāṇḍu, śira śūla, pārśva śūla, udāvarta, netra dāha, āsya dāha, hṛdroga, vyaṅga, nīlikā, netra srāvaṇa, nāsikā srāvaṇa, āsya srāvaṇa, halīmaka, śvāsa, kāsa, kāmalā, apacī, apasmāra, unmāda, vātarakta, yoni doṣa, reto doṣa, timira, arochaka, avipāka, chardi, svayathu, visphoṭaka.

विरेकसाध्या गुल्मार्शोविस्फोटव्यङ्गकामलाः|
जीर्णज्वरोदरगरच्छर्दिप्लीहहलीमकाः||
विद्रधिस्तिमिरं काचः स्यन्दः पक्वाशयव्यथा|
योनिशुक्राश्रया रोगाः कोष्ठगाः कृमयो व्रणाः||
वातास्रमूर्ध्वगं रक्तं मूत्राघातः शकृद्ग्रहः|
वाम्याश्च कुष्ठमेहाद्याः———————–| (A. H. Su. 18/8-9)

According to Ācārya Vāgbhaṭa, virecana is indicated in Gulma, arśas, visphoṭa, vyaṅga, kāmalā, jīrṇajwara, udara, gara, chardi, plīhā, halīmaka, vidradhi, timira, kāca, syanda, pakvāśaya vyathā, yoni roga, śukra roga,  koṣṭha roga, krimi, vraṇa, vātarakta, ūrdhvagata raktapitta, mūtrāghāta, sakrdgraha, kuṣṭha mehadya (diseases indicated for vamana i.e. starting from serial number kuṣṭha, meha and up to ūrdhva roga) are also eligible for virecana.

अविरेच्यास्तु सुभगक्षतगुदमुक्तनालाधोभागरक्तपित्तिविलङ्घितदुर्बलेन्द्रियाल्पाग्निनिरूढकामादिव्यग्राजीर्णिनवज्वरि– मदात्ययिताध्मातशल्यार्दिताभिहतातिस्निग्धरूक्षदारुणकोष्ठाः क्षतादयश्च गर्भिण्यन्ताः|| (Cha. Si. 2/11)

According to Ācārya Caraka, virecana is contraindicated in subhaga, kṣata guda, nāla nala, adhobhāga raktapitta, vilaṅghita, durbalendriya, alpāgni, niruddha, Kāmādi vyagra mānasa, ajīrṇa, madātyayita, ādhmāta, śalyardita, abhighāta, ati snigdha, ati rūkṣa, dāruṇa koṣṭha and other person having ailments beginning from kṣata and ending with garbhiṇī as described in vamana contraindication.

————————न तु रेच्या नवज्वरी||१०||
अल्पाग्र्यधोगपित्तास्रक्षतपाय्वतिसारिणः|
सशल्यास्थापितक्रूरकोष्ठातिस्निग्धशोषिणः|| (A. H. Su. 18/11)

Navajwara, alpāgni, adhogata raktapitta, ksata pāyu, atisāra, sa-śalya, āsthāpita,  krūrakoṣṭha, atisnigdha and śoṣa.

ग्रहणी कोष्ठस्थाग्न्यधिष्ठानभूता नाडी;

यदुक्तम्– “अग्न्यधिष्ठानमन्नस्य ग्रहणाद्ग्रहणी मता”  इति| 

(Cha. Su. 13/69.chakrapani)

Koṣṭha is the agni adhiṣṭhāna.

तत्र मृदुः, क्रूरो, मध्यम इति त्रिविधः कोष्ठो भवति | (Su. Chi. 33/21)

Three types of koṣṭha: Mṛdu, Madhyama and krūra.

Koṣṭha is assessed based on two factors – Agni and bowel habit

अपक्वं वमनं दोषं पच्यमानं विरेचनम्|
निर्हरेद्वमनस्यातः पाकं न प्रतिपालयेत्|| (Cha. Ka. 12/62)

Vamana occurs without the digestion of drug, whereas virecana occurs during the digestion of drug.

सर्वदेहप्रविसृतान् सामान् दोषान् न निर्हरेत्|
लीनान् धातुष्वनुत्क्लिष्टान् फलादामाद्रसानिव||
आश्रयस्य हि नाशाय ते स्युर्दुर्निर्हरत्वतः| (A. H. Su. 13/28)

Doṣas should not be eliminated forcefully in conditions like doṣas are mixed with āma, and are circulating all over the body and may be accumulated in the tissues and also not in the state of utkliṣṭa avasthā. Such an attempt is similar to taking the juice from an unripe fruit, which cause harm to the body.

Ācārya Vāgbhaṭa opined that by Śodhana auṣadha, if removing doṣas in the presence of āma it will destroy the body. Therefore prior to the Snehapāna/Śodhana Pācana-Dīpana should be carried out.

बहुपित्तो मृदुः कोष्ठः क्षीरेणापि विरिच्यते|

प्रभूतमारुतः क्रूरः कृच्छ्राच्छ्यामादिकैरपि|| (A. H. Su. 18/34)

In mṛdu koṣṭha person pitta is predominant, by taking kṣīra the person passes loose stools frequently. In krūra koṣṭha as vāta is predominant, person will not pass stool regularly or the person has kaṭhina or śuṣka mala pravṛtti.

मन्दाग्निं क्रूरकोष्ठं च सक्षारलवणैर्घृतैः |
सन्धुक्षिताग्निं स्निग्धं च स्विन्नं चैव विरेचयेत्  (Su. Chi. 33/39)

In mandāgni and Krūra koṣṭha patient sakṣāralavaṇayukta ghṛta should be given to the patient for 3-5 days for vāta śamana and then śodhana should be started.

दुर्बलः शोधितः पूर्वमल्पदोषः कृशो नरः||
अपरिज्ञातकोष्ठश्च पिबेन्मृद्वल्पमौषधम्| (A. H. Su. 18/49)

Administer the drug having mṛdu vīrya (mild potency) as well as alpa auṣadha(less in quantity) in aparijñāta koṣṭha (unknown bowels).

According to Ācārya Caraka: agni assessment depends on two criterias: Abhyavaharaṇa śakti and jaraṇa śakti.

Abhyavaharaṇa śakti is the capacity of intake of food. the quantity and quality of food varies from person to person. Some of the criterias taken into consideration are: the person not at all taking food, taking food in less quantity that too once in a day, taking food in less quantity that too twice a day, taking food in moderate quantity twice a day, taking food in normal quantity twice a day, taking food in excessive quantity twice or thrice a day. Here the scoring has been given to avara, madhyama as well as pravara.

Jaraṇa śakti: here jīrṇa āhāra lakṣaṇas are assessed. Mainly utsāha, laghutā, udgāra śuddhi, kṣudhā, tṛṣṇā, and yathocita malotsarga are taken into consideration. Here the lakṣaṇas are scored to avara, madhyama and pravara.

The knowledge of agni and koṣṭha is important, so as to decide the mātrā of auṣadha, Snehapāna mātrā, to assess the duration of snehapāna, selection of the auṣadha, to avoid complications, for planning of saṃsarjanakrama.