What are things brought down in Halacha that we do not do because of danger?

Although we cannot define the resultant danger in terms of medical science, we accept and adhere faithfully to our Sages' warning that eating fish and meat together is a danger (Pesachim 76b).

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    See Uncle Moishy Volume 11 D"H "Safety Way". I apologize for being sarcastic, but I think we're missing something here. – YDK Jul 22 '10 at 15:08
  • Although we cannot define the resultant danger in terms of medical science, we accept and adhere faithfully to our Sages' warning that eating fish and meat together is a danger(Pesachim 76b) For Shlomo and YDK who think it is just Hassidically-inclined. – SimchasTorah Jul 23 '10 at 14:35
  • There are things which Halacha allow us to Ignore but to say it about everything is an overstatement. – SimchasTorah Jul 23 '10 at 14:37
  • Yad Meir and Shevet HaLevi hold that this Halachah is no longer relevant because Tosfot states that certain ruach ra’ah do not descend in “these countries”. We can infer from Tosfot that we do not have to be concerned for any ruach ra’ah unless we have a mesorah that that specific form is still prevalent. Yad Meir and Shevet HaLevi cite Hago’ot Mordechai as a source for adopting such an approach regarding leaving eggs, onions and garlic overnight. They are supported by the fact that the Shulchan Aruch cites certain dangerous activities listed in the Gemara but not these. – SimchasTorah Jul 23 '10 at 14:40
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    @SimchasTorah Perhaps you meant to cite some other gemara? That one just says not to cook fish and meat together, not to avoid eating them together or certainly in sequence. – Double AA Nov 9 '12 at 1:28

Here's a list of things that are fobidden, according to the Kitzur Shulchan Aruch

Kitzur Shulchan Aruch 4:2 - Not urinating when one has the urge

Kitzur Shulchan Aruch 6:5 - Not pouring out water in homes next to where a person died

Kitzur Shulchan Aruch 32:17 - Drinking very cold water when tired

Kitzur Shulchan Aruch 33:

  • 1: Eating meat with fish or fowl, even if one just cooked them together

  • 3: Sweat except from the face. Puting money in one's mouth

  • 4: Swallowing one's saliva after smelling delicious food

  • 5: Drinking water that was left uncovered

  • 6: Eating food or beverages that were under a bed that was slept on.

  • 7: Walking under a shaky wall, on a rickety bridge, walking alone at night, sleeping alone in a room, drinking water from rivers at night, putting one's mouth on a water spout to drink

  • 9: Eating food that is disgusting

  • 11: Chopping down fruit trees unless the wood is worth more than the fruit, or it's preventing other fruit trees from growing.

  • 12: Putting a non-sealed cup/bottle of hot water on one's stomach

  • 13: Walking through a fast flowing river if the water is higher than one's waist

  • 14: Mentioning potential trouble that could befall one

Kitzur Shulchan Aruch 161:20 - Cutting of Polish plaits

Kitzur Shulchan Aruch 177:

  • 6: After cleaning the corpse (Tahara): leaving the corpse on the cleaning table or turning the cleaning table upside down

  • 7: Kissing children that have died, or holding the corpse's hand and asking to be taken with them

Kitzur Shulchan Aruch 199:13 - Leaving a freshly dug grave open overnight

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    Where did you get this list? We are discussing here judaism.stackexchange.com/questions/84492/… how it contains a mistake – SAH Aug 3 '17 at 19:53
  • @SAH - I didn't "get" this list, I created it by taking notes while learning the Kitzur over 2 dozen times, and translating the results. – Danny Schoemann Aug 6 '17 at 12:57

What things are dangerous?

A.) Anything currently recognized by today's conventional medicine as dangerous.

B.) Anything codified into Halacha as dangerous.

The majority of medicinal statements in the Talmud were not codified into law by the Rambam or others. (In the 900s, the head of Babylon's yeshiva of Pumbedisa, R' Sherira Gaon, wrote: "the rabbis of the Talmud were not doctors, and wrote down the medicine of their day; do not attempt any Talmudic medicine unless our expert doctors today have established that it could do no harm.) The Rambam himself wrote in his medical advice as Halacha (parts of chapter 4 of Laws of Personality Traits), and again much of that did not make it into later sources of straight Halacha.

Something like "don't put coins in your mouth because diseased people may have handled them" appears Talmudically on down, and makes sense from our medical perspective today. "Don't eat fish and meat together" is the interesting exception, something that doesn't seem to be borne out by medicine today, but clearly made it into all the halachic sources (Shulchan Aruch etc.). The Magen Avraham (commenting on OC173:2) acknowledges this is the exception to the rule, and shrugs his shoulders at how it came to be halacha.

Today, if you have a custom about these other safety things that appeared in non-canonical sources, by all means keep your custom, or talk to your rabbi if you feel you can't. Many such customs are described in the other answers here. Works such as the Hassidically-inclined Kitzur Shulchan Aruch have incorporated many such customs, and today we've seen a literary explosion of new books on these topics. If you have no such customs but feel it's right for you to adopt some of them, talk to your rabbi. If you have no such customs and don't want to adopt any, you're fine sticking with A. and B. above.

  • what about all the traditional warnings about water? They seem to be in the category of fish+meat, i.e. no modern scientific justification – Jeremy Jul 23 '10 at 13:51
  • Jeremy, which warnings? Like water left out overnight in places where poisonous animals may have been lurking? To the best of my knowledge those didn't make it into later straight-halacha sources (again, don't quote me Kitzur S"A). Or more accurately, that's not usually our situation today. Again, fish+meat is the weird one that was canonized into halacha. – Shalom Jul 23 '10 at 14:04
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    "currently recognized by today's conventional medicine as dangerous"? Really?! What about eating hardly any vegetables, never exercising, not getting adequate sleep, using a communal towel after netilas yedayim for the entire family and shabbos guests, etc? I certainly don't see people getting "machmir" about those things nearly as much as mixing fish and meat – Desert Star Dec 21 '10 at 21:36
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    @Desert star: old practices are hard to kill; and things like healthy eating, exercise, etc. are hard. Superstitions are easy. – Shalom Dec 22 '10 at 15:19
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    which Magen Avraham? – ertert3terte Jul 11 '13 at 17:16

1) Eating onions or garlic left overnight - there are ways around this, and some are not stringent about this nowadays

2) There are the various things mentioned in Tzavaas R' Yehudah Hachassid, such as not closing up a window or door, not having two brothers live in the same city, being careful about identical names when considering a shidduch, etc. etc.

3) Drinking water from a stream without checking for leeches

4) The practices mentioned in Yoreh Deah 116 - not putting money in one's mouth, not to eat sweat, and others.

5) The Sefer Shemiras HaGuf V'Hanefesh discusses just about everything on this topic.

  • Have you heard of the no water after fish one? – SimchasTorah Jul 22 '10 at 7:02
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    Yes. I think that is why some people drink a shot of shnapps after the fish at the Shabbos meal. Though there might also be other motivations for that... – Dave Jul 22 '10 at 13:31
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    as my great uncle A"H used to say for the fish+shnapps: "The fish have to swim!" (of course, this would suggest water is better for this, but as you say, there may be other motivations at work) – Jeremy Jul 23 '10 at 13:49

If one follows the RCA smoking goes in this category.

(See also)


There are also things that are only "semi-dangerous" that should be avoided during the 9 days, like certain travel. I have a friend who broke up with a girl he was dating because she went sky-diving during the 9 days. I wonder what category that would have during the rest of the year...

  • I sense that sky-diving may not have been the only issue... – DanF Aug 2 '17 at 16:27

Rabbi David Sedley has two pdf files on his website, where he brings the sources for different dangerous foods in Gemara and Halacha. Scroll down to the bottom of the page. These are from classes given at Midreshet Rachel v'Chaya.

Halachically Speaking Volume 3 Issue 9 (Avoiding Danger) also talks about many things that Torah considers dangerous.


1)There is of course Fish and Meat

2)Milk and Fish according to Sefardim and Minhag Chabad and some other Chassidim

3)Drinking water immediately after eating fish.SH"UT Rabbi Akiva Eiger says that the warning against drinking water shortly after eating fish is even today.It is also brought by the Kaf Ha'haim and the Aruch Ha'shulhan

  • Cheese/butter and cream are different according to Minhag Chabad. Milk as well as cheese is a problem, however butter isn't because it's not pure milk. (look in Shaarei Halacha uminhag as well as the Reshimos mentioned there) – Joe Shmoe Oct 7 '10 at 5:25
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    someone once told me (without a source), that the danger of eating fish and meat together is because fish have small bones that may be overlooked when eating meat (which only have big bones). This could lead to inadvertently swallowing small fish bones, which could lead to choking, etc. I'd never heard that before, and the danger mentioned in shulchan aruch is Dover Acher, or Tsaras (leprosy, for lack of a better translation) - Shulchan Aruch Yoreh Deah 116:2, Orech Chaim 173:2. Anyone heard about the bones? – Menachem May 31 '11 at 16:53
  • @Menachem Just off the cuff I seem to remember that being the Meiri's opinion on the gemara over there in ?pesachim?. – Double AA Oct 12 '12 at 18:05

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