I would like to give a few examples and analogies to continue the theme of the usage of officinal substances in pre-colonial Tamil Siddharas, some Theravada branches and others. The Patañjali’s Yoga-sūtras (concretely in the Sādhana pāda) use the concepts of the four fundamentals (चतुर्व्यूह caturvyūha) for getting rid of suffering. They are very similar to what we find in Āyurveda, namely: हेय heya – existence of suffering; हेय हेतु heya hetu – a cause of suffering ; हान hāna – stopping of suffering; हानोपाय hānopāya – methods of getting rid of suffering. In the context of Āyurveda, upāya involves the use of dietary regulation, herbs, etc. Also, it identifies the causes of disease, approach to preventively remove the disease possibility, etc. In the context of yoga, upāyas are the aṅgas of the aṣṭāṅgayoga (the eight-part yoga). What is interesting is that there are many in India who believe that Patañjali is the author of the Yoga-sūtras and he is also associated with one of the works on Āyurveda. Though of course many western scholars disagree with this. In the Nāthas, Patañjali may be associated with one of the Nine Nāthas, specifically Acal Achambhenāth, a manifestation of Ananta Śeṣa.

However, if we go back to the similarity of getting rid of suffering, in the form of disease (in Āyurveda) and getting rid of ‘duhkkha’ suffering (in yoga), through yogic sādhana and path, one level can be a lead-in to the other or even sometimes be a complementary. External rasāyana can gradually shift the focus to the inner alchemy, which is essentially yoga. We see a similar approach in the Nāth–yoga, for example, at a gross level, the practitioner uses neti, sūtra-neti, jala-neti practices and etc. Then, when the body is sufficiently purified, the practitioner can gradually shift to the inner alchemy, which is essentially yoga. After that, nāḍī-śuddhi is practised instead, mantras are used instead of external ‘healing substances’. In short, the practice goes to a more subtle level. In Tantrism, I have even come across a context of mantras called ‘mantrauṣadhi’ (mantras as substitutes for plants). The meaning is that mantras are able to relieve suffering (disease) like plants. In the case of mantra-yoga, just as the synthesis of different plants yields a healing potion or alchemical substance, so too combinations of mantras yield the elimination of a particular problem. For example, the combination of syllables, tantric bījas can form mantras with different capabilities (siddhis). Of course, the implication is that all this works only with an infallible understanding of such methods, which is possible with learning from a guru who has realised the relevant siddhis.