NASU- (Av. nasao- f., nasuš- n.; MPers. nas; nasuš; nasrušt), the demon of carrion, the greatest polluter of Ahura Mazdā’s world.

The most evil manifestation of the demons is the Nasu-/Nasuš, which attacks the body when it comes into contact with dead matter, especially human and animal dead bodies, with bleeding, notably menstruation, and in connection with the trimming of hair and nails. The affliction of corpses by Nasu-/Nasuš provided the basis for the Zoroastrian abhorrence of everything that is dead. As soon as a dying person loses consciousness, Nasu-rushes upon the body, generates pollution from decaying bodies, and contaminates all that comes in contact with it. In the Avesta it is depicted as a repellent fly, with crooked knees, projecting buttocks, and ceaseless dribbling (maxši.kəhrpa ərəγaetiia. frašnaoš apazaδaŋhō akaranəm.driwiiå; Vd. 7.2).

The Bundahišn describes Nas Demon as the one who causes the pollution and contamination (Nas dēw ān kē rēmanīh ud nasruštīh kunēd kē nasā xwānēnd, Bund. TD1, fol. 78r.; DH fol. 213r.; Anklesaria, chap. XXVII.37, pp. 240-41). According to the Dādestān ī dēnīg (chap. 16.6), when she becomes triumphant over the soul of the righteous man and drives it out from the body, she makes a place for herself in it; then the body for that reason is called a corpse (nasā).

As stated in the Zoroastrian funerary regulations, a corpse is to be exposed naked and carried by two people, because the act of carrying it alone will involve full contact with it that would spread the pollution even more. Nasu- attacks a person who carries a corpse alone through his body openings, beginning with the nose, eyes, tongue, and jaws, and ending with the penis and anus (Vd. 3.14; 8.23-25). To counteract its influence and lessen the likelihood of contamination, the ritual of sagdīd “seen by a dog” has to be performed as soon as possible after death (Vd. 7.3; 8.16). The Dēnkard explains that the reason is that, when a dog looks at the exposed face of the corpse, its gaze has the power to contain the demons of dead matter within the body, preventing them from escaping and contaminating the living world (ed. Madan, p. 463; ed. Amouzgar and Tafazzoli, chap. 24.19a). According to the Dādestān ī Dēnīg (chap. 16.13), by the performing of the sagdīd ritual, Nasu- becomes less of a corpse and more like hixr, i.e., dry dead matter, and less polluting.

An individual contaminated by that demon can regain purity with the aid of a qualified purifier (Vd. 9.42), but if an unqualified one attempts to perform the purificatory rites, Nasu- becomes stronger and increases diseases, deaths, and adversities (Vd. 9.48). The Avesta recommends a combination of recitation of certain verses of the Gāthās twice (Y. 28.1, 35.2, 39.4, 41.3, 41.5, 47.1, 51.1, 53.1), thrice (Y. 27.14, 33.11, 35.5, 53.9) and four times (Y. 27.13, 34.15, 54.1; [Vd. 10.1-12]) and purification rites such as the Barašnom to command Nasu- to leave the body.

The Srōš bāj, also called the Bāj-e nasrūšt “Utterance against pollution,” which is an important daily drōn recitation performed in honor of Sraoša, is a powerful prophylactic prayer that protect one against decay and death (see Kreyenbroek, pp. 144-52, with text and tr. of the bāj); and Saddar Nasr 35 recommends the recitation of the prayer Kəm nā Mazdā (Y. 46.7, Y. 44.16, Vd. 8.21 and the third line of Y. 49.10).

See also BURIAL iii. In Zoroastrianism; CLEANSING i. In Zoroastrianism; CORPSE; DOG ii. In Zoroastrianism.


J. Amouzgar and A. Tafazzoli, Le Cinquième livre du Dēnkard, Paris, 2000.

B. T. Anklesaria, Zand-Ākāsīh: Iranian or Greater Bundahišn. Transliteration and Translation in English, Bombay, 1956.

M. Boyce and F. M. Kotwal, “Zoroastrian bāj and drōn I, II,BSOAS 34, 1971, pp. 56-73, 299-313.

[Bund.] F. Pakzad, Bundahišn Zoroastrische Kosmogonie und Kosmologie, Band I Kritische Edition, Tehran, 2005.

[Dādestān ī Dēnīg] M. Jaafari-Dehaghi, Dādestān ī Dēnīg, part I. Transcription, Translation, and Commentary, Paris, 1998.

[Dēnkard] D. M. Madan, ed., The Complete Text of the Pahlavi Dinkard, 2 vols., Bombay, 1911.

G. Kreyenbroek, Sraoša in the Zoroastrian Tradition, Leiden, 1985.

[Saddar Nasr] E. B. N. Dhabhar, Saddar Nasr and Saddar Bundehesh, Bombay, 1909.

[Vd.] M. Moazami, Wrestling with the Demons of the Pahlavi Widēwdād. Transcription, Translation, and Commentary, Leiden and Boston, 2014.

(Mahnaz Moazami)

Originally Published: August 24, 2016

Last Updated: August 24, 2016

Cite this entry:

Mahnaz Moazami, “NASU,” Encyclopædia Iranica, online edition, 2016, available at (accessed on 24 August 2016).