The above definition explains that Grahi action is the one that has the ability to improve appetite, digestion along with correction of body metabolism. It also exhibits the major effect of correcting the consistency of stools (पुरीष). Even though the word मल/mala is being mentioned in the reference and most of them consider it as waste bye-products of food (आहारमल). But when considered in a broader sense it envisages all the metabolic bye-products that are produced in every corner of the body and are then transported out as waste bye-products. 

As such the action is mainly seen as the one that absorb the excessive moisture or fluidity present in the bye-product. Here when the food wastes are considered as a gross one, the stools become the standing example of action. As per Ayurveda, there are different मल/Mala that are supposed to be produced when the formation of धातु/Dhatu happens. When there is improper formation of these मल/Mala then it leads to relative disturbance in the body. 

It is to be noted that the मल/Mala mentioned as धातुमल/ Dhatumala are different from the त्रिमल/Trimala and hence consideration of पुरीष/Pureesha only as मल/Mala in the context will be a flaw. 

Every action is resultant of the properties present in the substance. Here as mentioned in the reference, the property that is mainly responsible for this action is the उष्ण/Ushna property. Other than this there is a sub activity that happens namely शोषण/Shoshana which is related to the property रूक्ष/Ruksha. Thus the actions is the resultant of two main properties namely उष्ण/Ushna and रूक्ष/Ruksha. These two properties complement each other in bringing out the desired effect. 

Basically, the properties inculcate two methods parallelly namely the action of दीपन/Deepana & पाचन/Pachana. Here the उष्ण/Ushna property is responsible for the initiation of the action. Due to this activity, there will be metabolism of the unmetabolised matter (आम/AMA). This inturn leads to proper absorption thereby giving the final effect of ग्राहि/Grahi action namely the absorption of secretion or fluids or moisture leading to normalisation of waste formation. Moreover, the use of these are also useful in the removal of moisture (present in excess) of पित्त/Pitta and कफ/Kapha Dosha too.

The action is possibly due to the influence exerted by वायु/Vayu, अग्नि/Agni and पृथ्वी/Prithvi महाभूत/Mahabhuta where the substances that are predominant will show the effect in different levels of the activity. Accordingly, The वायु महाभृत/Vayu mahabhuta substance that are usually dominated with रूक्षगुण/Rukshaguna predominant along with तिक्तरस/Tiktarasa and शीतवीर्य/Sheetaveerya will suppress the secretion or precipitation which dries the metabolic bye-products leading to normalisation of them. On the other hand अग्नि महाभूत/Agni mahabhuta substance are usually dominated with उष्णगुण/Ushnaguna predominant with कटुरस/Katurasa and उष्णवीर्य/Ushnaveerya lead to drying of the bye-products due to increase in the process of digestion whereby the moisture is used for the process leading to normalising of the consistency. Finally, the पृथ्वी महाभूत/Prithvi mahabhuta dominant substances associated with गुरु/Guru and रूक्षगुण/Rukshaguna along with कषायरस/Kashayarasa and शीतवीर्य/Sheetaveerya just absorb the excessive moisture leading to the normalisation of the consistency. Even though the methodology of action is different the effect is the same namely द्रवशोषण/Dravashoshana or removal of excessive moisture.