ETYMOLOGY

According to vācaspatya: term virecana has three components

Vi- upasarga

Ricir-Ric dhātu

Lyut- pratyaya

According to Śabdakalpadruma: ‘Rici’-dhatu.’Vi’-upasarga with ‘Ṇic’ and ‘Lyut’- pratyaya.

DEFINITION

विरेचनशब्दार्थं विभजते– अधो गुदेन दोषनिर्हरणं भजत इति अधोभागम्| वमनविरेचनयोरपि कदाचिद्विरेचनसञ्ज्ञां षड्विरेचनशताश्रितीयोक्तां दर्शयन्नाह– उभयमपीत्यादि| 

(Cha. Ka. 1/4 Cakrapani commentary)

The word virecana is commonly used for evacuation. As both vamana and virecana do the evacuation of doṣas, sometimes virecana broadly applies for both. But generally, virecana indicates the evacuation of doṣas through guda.

तत्र दोषहरण, अधोभागं विरेचनसञ्ज्ञकम्; 

उभयं वा शरीरमलविरेचनाद्विरेचनसञ्ज्ञां लभते|| (Cha. Ka. 1/4)

Expulsion of doṣas through the adhobhāga is virecana. Ācārya Cakrapāṇi comments adhobhāga’ to gudā mārga. In certain circumstances expulsion of doṣas through both ūrdhva and adhobhāga are termed to be known as virecana. 

पित्ते तु विरेकं श्लेष्मसंसृष्टे वा तत्स्थानगते वा श्लेष्मणीति॥ (A. S. Su. 27/4)

Virecana is administered for vyādhis vitiated due to pitta, pitta associated with kapha and also in pitta sthāna gata kaphaja vyādhi.

पित्तहरैर्मात्रां कालं च प्रमाणीकृत्य; विरेचनं तु सर्वोपक्रमेभ्यः पित्ते प्रधानतमं मन्यन्ते भिषजः; तद्ध्यादित एवामाशयमनुप्रविश्य केवलं वैकारिकं पित्तमूलमपकर्षति, तत्रावजिते पित्तेऽपि शरीरान्तर्गताः पित्तविकाराः प्रशान्तिमापद्यन्ते, यथाऽग्नौ व्यपोढे केवलमग्निगृहं शीतीभवति तद्वत्||१६|| (Cha. Su. 20/16)

Virecana treatment is for pitta doṣaḥ nirharaṇa. As Āmāśaya is the sthana for Kapha and pitta, subsiding the āmāśayagata pitta, all other types of pitta also gets subsided. As how a fire caught in a building gets cooled by subsiding the fire.

विरेचनं पित्तहराणां|| (Cha. Su. 25/40)

Virecana is best treatment for pitta hara.

बुद्धिप्रसादं बलमिन्द्रियाणां धातुस्थिरत्वं ज्वलनस्य दीप्तिम्|
चिराच्च पाकं वयसः करोति संशोधनं सम्यगुपास्यमानम्| (A. H. Su. 18/60)

By virecana karma, it enhances buddhi, indriya bala, dhātu sthiratva, does agni dīpti and delays ageing.

Virecana has its action on Doṣa, Dūṣya and Srotas.

Doṣa wise – it acts mainly on pitta.

                       Pitta sthānagata kapha

                       Kapha sthānagata pitta

                       Pittāvṛta vāta

                       And to some extent to saṃnipātaja doṣas.

Dūṣya wise – has action on Rasa, Rakta, Māṃsa, Asthi, Majjā and Śukra

Srotas – has action on Rasavaha, Raktavaha, Māṃsavaha, Asthivaha, Majjāvaha and Śukravaha.

Health wise – it is done as a part of ṛtucaryā in Śarad ṛtu. As in Śarad Ṛtu pitta prakopa occurs, so virecana is opted as a ṛtu śodhana during this season.

Disease wise virecana is opted as the line of management for kuṣṭha, śotha, śvāsa, pakṣāghāta,etc.

बुद्धेः प्रसादं बलमिन्द्रियाणां धातुस्थिरत्वं बलमग्निदीप्तिम् |
चिराच्च पाकं वयसः करोति विरेचनं सम्यगुपास्यमानम् ||

यथौदकानामुदकेऽपनीते चरस्थिराणां भवति प्रणाशः |
पित्ते हृते त्वेवमुपद्रवाणां पित्तात्मकानां भवति प्रणाशः || (Su. Chi. 33/27-28)

By virecana karma, it does buddhi prasādana, does indriya bala, dhatu sthiratva, bala vardhaka, does agni dīpti, delays ageing process. By the removal of water, how all the reliants of water gets destroyed. In the same way, by the removal of pitta doṣa through virecana, it gets rid of all the diseases caused due to pitta.