Right in the beginning of Shulchan Aruch we see this idea of "Ruach Rah". In regards to washing ones hands and all that comes before that -- not walking more than 4 amos without washing one's hands, not touching orifices of the body without washing ones hands. All done in order not to cause a danger to someone. Is there any explanation that can be given to understand better what Ruach Rah is, where it comes from. What sources could be quoted about this.

My reason for asking this is because I am learning with someone now for a half hour a day and he would like a better explanation in this inyun of Ruach Rah (like I stated above, where it comes from, why, how does it "work", etc.)


2 Answers 2


It's difficult to explain it as simply being bacteria, as the Gemara (Pesachim 112a) clearly says that food under bed gets contaminated with ruach ra'ah even if it was properly sealed.

Interestingly, there is a machlokes as to whether ruach ra'ah even exists nowadays! According to Rambam there are other reasons why you can't place food under bed nowadays. Tosafos (Yuma 77b) and Maharshal (Yam Shel Shlomo, Chulin 8:31) concur. See http://doseofhalacha.blogspot.co.uk/2014/05/food-under-beds.html

Rav Eliezer Melamed explains that it disappeared along with prophecy. It was a mystical evil spirit that shouldn't bother us so much today. http://ph.yhb.org.il/02-08-04/

At times, it means a melancholic, depressive state. Thus, King Saul was struck with this depression (Shmuel I 18:9) upon losing the kingship.

Most often, though, it is understood as a fraction (or akin to) death. Thus, the Beis Yosef (OC 4) writes that ruach ra'ah only descends upon one when they sleep. He compares it to Yaakov's struggle with the angel, and explains the connection with death. This is why one can't take food into a cemetery, etc. either. (See Rambam, Hilchos Rotzeach 12:5). It is for this reason that we wash our hands after leaving a cemetery, too.

  • +1, but could you expand on exactly what it is? You explained where it comes from, and perhaps what it is related to. But what it does or how it works could use clarification (what about death happens to you). Commented May 29, 2014 at 19:41
  • I believe I did according to the first couple of explanations, though it is difficult to explain the 3rd, and main explanation: that there's an element of death - especially when Rambam (+ others) don't believe it exists today.
    – Zvi
    Commented May 29, 2014 at 19:45
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    Ya - I was referring to the final explanation, thus the parenthetical remark. Sorry for the ambiguity. Commented May 29, 2014 at 19:46

Rabbi Ahron Soloveichik explained to me that "Ruach Rah" is referring to things like bacteria and germs.

Our Chachamim, Sages, were very advanced thinkers. They must have seen certain cause and effect. If you don't wash your hands disease etc is transferred. They obviously did not have a microscope to see the bacteria or germs, however they identified a physical cause to the harm. They referred to this as Ruach Rah.

  • Hmm, maybe......
    – Yehoshua
    Commented Mar 5, 2013 at 22:58
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    @Yehoshua Do you have another working theory?
    – RCW
    Commented Mar 5, 2013 at 23:39
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    !!! I'm not an apikorus?! W00t!
    – Seth J
    Commented Mar 6, 2013 at 1:46
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    @Yehoshua He made no mention of another source. However, I was just thinking about the premise of your question for a "Makor". Any source that would explain Ruach Rah as a currently identifiable physical phenomena like germs would have to be pretty recent coinciding with medical/scientific discovery. If that were the case the "Mekor" I would imagine would be equally as qualified as Rav Soloveichik to provide an explanation. Therefore, wouldn't really add much other than having another great mind agree.
    – RCW
    Commented Mar 7, 2013 at 1:20
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    @SethJ I am glad we can help you with that burden!
    – RCW
    Commented Mar 15, 2013 at 0:35

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