Nose is one among the Panchadnaanendriya, whose functions are not only limited to ol-faction and respiration but also considered as a pathway for drug administration.So the drug ad-ministered through nose as Nasya reaches to the brain and eliminates the morbid Doshas respon-sible for producing the disease. Present article shows, actual drug administered in nose how it will probably act on vital points located in brain and also how it will act on organs related to the-se points.e.g.in AshtangaSamgraha it is explained that Nasa being the entry to Shira, the drug administrated through nostril reaches Shringataka -a SiraMarma by Nasastrotas and spreads in the Brain reaches at a junction place of Netra , Shrotra , Kantha, Siramukhas (openin.g of the vessels) etc. and remove or detach the morbid Doshas present above supraclavicular region and expel them from The Uttamanga.
Nasya kala i.e. proper time and duration of drug administration is important factor. Age, Dosh avastha, vyadhiavastha, Form of drug used is also important factor in Nasya karma. Keeping in the view of the above said facts, it can be concluded that either the essence of Nasya or Nasyadravya is reaching the brain and acting on im-portant centers controlling different neuro-logical, endocrine and circulatory functions and thus showing systemic ef-fects.Following things should be consid-ered in case of drug used.PH & osmolarity & concentration of drug used are important factors for absorption of drug through nasal passage. Bioavailability can be affected by concentration of drugs like Salt, honey etc. Various delivery systems affect the site of deposition, degree of absorption. Viscosity increases the contact time between nasal mucosa & drug, which enhances the poten-tial of the drug action.In Mechanism of drug absorption, Transcellular passive dif-fusion, Drug diffuses through membrane. It is an active transport process. More suitable for lipophilic drug, snehanasya may absorb through this process.Para cellular passive diffusion- drug is transported between the cells and transcytosis by vesicle carrier. It is a suitable mechanism for hydrophilic drugs e.g. avpeedak, dugdhs &kwathnasya.