तत्रोष्णतीक्ष्णसूक्ष्मव्यवायिविकाशीन्यौषधानि स्ववीर्येण हृदयमुपेत्य धमनीरनुसृत्य स्थूलाणुस्रोतोभ्यः केवलं शरीरगतं दोषसङ्घातमाग्नेयत्वाद् विष्यन्दयन्ति, तैक्ष्ण्याद् विच्छिन्दन्ति, स विच्छिन्नः परिप्लवन्  स्नेहभाविते काये स्नेहाक्तभाजनस्थमिव क्षौद्रमसज्जन्नणुप्रवणभावादामाशयमागम्योदानप्रणुन्नोऽग्निवाय्वात्मकत्वादूर्ध्वभागप्रभावादौषधस्योर्ध्वमुत्क्षिप्यते, सलिलपृथिव्यात्मकत्वादधोभागप्रभावाच्चौषधस्याधः प्रवर्तते, उभयतश्चोभयगुणत्वात्| इति लक्षणोद्देशः||              (Cha. Ka. 1/5)

सरत्वसौक्ष्म्यतैक्ष्ण्यौष्ण्यविकाशित्वैर्विरेचनम् |वमनं तु हरेद्दोषं प्रकृत्या गतमन्यथा || यात्यधो दोषमादाय पच्यमानं विरेचनम् | गुणोत्कर्षाद्व्रजत्यूर्ध्वमपक्वं वमनं पुनः ||                                                                                                (Su. Chi. 33/33-34)

Dravyas having uṣṇa, tīkṣṇa, sūkṣma, vyavāyi and vikāsi properties, reaches the hṛdaya by virtue of its vīrya and circulates through the dhamanis. By the āgneya property it causes viṣyandana. By the tīkṣṇaguṇa it separates the adhered doṣas located in the sthūla and aṇusrotas of the śarīra. Like honey kept in a pot smeared with sneha. The doṣas, after separation moves without adhesion in the body which has undergone snehana. finally, the aggravated doṣas reaches the āmāśaya and by the predominance of pṛthvī and jalamahābhūtas, and also by the prabhāva moves downwards and expels out through gudamārga.

UṢṆA: uṣṇavīrya possess the function like vilayana and has the property to decrease vāta and kaphadoṣa. In modern it is having a catalytic action. Which converts the saturated compounds to unsaturated ones.

TĪKṢṆA: according to ĀcāryaSuśruta: tīkṣṇa is a property producing pāka, dāha and srāva, whereas Carakācārya defines tīkṣṇaguṇafunctions for vicchindana.

SŪKṢMA: By this property, the dravyas reaches the sthūlaand aṇusrotases. and clears the doṣas from that site and are brought to āmāśaya for virecana.

VYAVĀYI: by this property, the dravyas without absorption rapidly spreads for further action. According to ḌalhaṇaĀcārya, the dravyas after reching to cellular level, it affects the body like madya and viṣa.

VIKĀSI: this property detaches the dhātubandhana, and also permeate through the whole body without digestion like that of vyavayi.

SARATVA: ĀcāryaSuśrutamentioned this property, which means anulomatva.

PRABHĀVA: According to Cakrapani, due to the pancamahābhautika constitution, the predominance of pṛthvīand ap mahābhūta, there is a tendency of adhogati of virecana drugs. It is initiated by the apānavāyu.

Śodhanadravyas are mild irritants to the stomach and intestinal mucosa respectively, to cause inflammation. By this the permeability of the membrane changes and those morbid materials which come out due to the changed permeability which cannot come out in normal condition. The induced mild inflammation facilitates quick absorption of the vīrya of the dravyas in initial stage. Later it does the excretion of the morbid doṣas which generally not excreted through the mucosa of gut. It is because of the inflammation that increases the permeability of the capillaries, which in turn allow the absorption, as well as the excretion of such substances which are not allowed in the normal condition. The process of defecation involves the contraction of rectum and relaxation of internal and external anal spincter. In this the distention of stomach by food causes contraction to rectum. The strong contraction and relaxation of anal sphincters occurs due to the reflex mediated by parasympathetic nerves and the reflex centre in the sacral segment of spinal cord. In kaphantamvirecanam, kapha may be co related with the mucous which is secreted by the goblet cells of intestine. Mucous is a glycoprotein. During snehana and swedana, the duśītakapha comes in the goblet cells and are excreted out during virecana.

Modern view:

Laxatives probably induce limited lowgrade inflammation to promote accumulation of water and electrolytes and stimulates intestinal motility. Similarly, shodhanadravyas are mild irritants to the stomach and intestinal mucosa. Due to this, the permeability of the membrane changes and the substances come out due to the changed permeability. The mass movement of the faeces drives into the sigmoid or pelvic colon. The process of defecation involves the contraction of rectum and relaxation of internal and external anal spincter. In this the distention of stomach by food causes contraction to rectum. The strong contraction and relaxation of anal sphincters occurs due to the reflex mediated by parasympathetic nerves and the reflex centre in the sacral segment of spinal cord.

Bulk purgatives: are non-metabolising, retains water and promotes peristalsis.

Faecalsoftners – as dioctyl sodium sulphosuccinate.

Osmotic purgatives – accelerates transfer of gut contents through small intestine to colon, large volume in colon results in purgation.

Stimulant purgatives – stimulates the mucosa of gut. and irritates local reflexes.