Shalya Tantra or Surgery
It deals with the Shalya in the body and the methods for its elimination from the body. It deals with the means such as Yantra (Tools), Shastra (Instruments), Kshar (Alkalis) and Agni (Fire).
Shalya is defined as anything that cause discomfort to the body and mind. It is of two types, Shaarir (within the body) and Aagantuj (outside the body). Shaarir (inside the body) : Shalya which is present inside the body is considered as Shaarir Shalya. like Unhealthy teeth, Hair, Nails, imbalanced Doshas, Dhatus and Mala, abscess, tumor etc.
Aagantuj Shalya which is from outside the body is called Aagantuj. like Thorns, Stone pieces, iron pieces, dust particles etc