Agnihotra (IAST: Agnihotra, Devanagari: अग्निहोत्र) refers to the twice-daily heated milk offering made by those in the Śrauta tradition. This tradition dates back to the Vedic age; the Brahmans perform the Agnihotra ritual chanting the verses from the Rigveda. The tradition is now practiced in many parts of South Asia in the Indian sub-continent, including primarily India and most particularly in Nepal. The Brahman who performs Agnihotra ritual is called Agnihotri.
The history of Agnihotra ritual — the casting of cow milk (or ghee) into the fire, at every sunset and at every sunrise — has been traced from Indo-Iranian fire-worship of the Zoroastrians, as seen in Yasna Haptaŋhāiti in the Old Avestan. This became popular in India with Upaniṣads.
Witzel (1992) locates the first Agnishala hypothetically at Jhul (Mātātīrtha), in the western ridge of the Kathmandu valley and later at the southern rim of the palace of Aṃśuvermā at Hadigaon, Kathmandu. The first source of inscription evidence was from Tachapal tole, east part of Bhaktapur city, also shown by a legend that the Maithila King Harisiṃhadeva would establish the yantra of Taleju Bhavānī in the house of an Agnihotri. From 1600 CE onward, the Agnihotra has been attested to Patan only.
The Agnihotra ritual in Nepal has been first recorded in an inscription of King Anandadeva in c. 1140 AD that mentions of the initiations of his two sons, viz. Yasomalla and prince Somesvara at Agnimatha (or Agnishala in Lalitpur). The temple of Agnishala since the 12th century (or before?) still maintains the Vedic tradition of Agnihotra fire sacrifice ritual and has since then undergone many ritual changes. However, the basic Vedic performance is still intact.