I've started learning Mishna Brura and I've come across ruach raa in the sefer's discussion of hilchot netilat yadayim.

Is ruach raa simply another word for tuma, does it refer to smell, or some other concept entirely?

  • Can you edit in a more precise citation to help people see what you are referring to?
    – Double AA
    Commented Mar 6, 2017 at 16:00

1 Answer 1


The source for this ruah ra'ah is Shabbat 109a:

רבי נתן אומר: בת חורין היא זו, ומקפדת עד שירחוץ ידיו שלש פעמים

That is, there is an entity referred to as "bat horin" which is said to be belligerent (my best attempt at translation in context) until a person washes his hands three times.

Rashi there describes this entity as a 'ruah':

בת חורין היא - הרוח

See Rashi to Eruvin 45b s.v. ruah ra'ah who identifies ru'ah ra'ah with demons:

או רוח רעה - שנכנס בו שד

It thus appears that ruah means a spirit or demons, and that a ruah raah, is a bad, i.e. malevolent or harmfull spirit.

Related: https://judaism.stackexchange.com/a/61019/8775.

  • 1
    Demon got your tongue commentless downvoter?
    – mevaqesh
    Commented Mar 5, 2017 at 6:14
  • @theideasmith if you like an answer, consider marking it correct.
    – mevaqesh
    Commented Mar 8, 2017 at 14:05

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