Siman 191 — Blood Found While Urinating (דם בהשתנה): a Wound in the Bladder or Kidney, the Mokh Bedikah, and Medical Diagnosis
A single, dense seif — seven rules to tell the blood of a wound from the blood of nidda
יורה דעה · סימן קצ״א
דין אשה שמצאה דם בהשתנה
🌱 Introduction Level · מתחילים
✦ ❖ ✦
A first approach to Siman 191: its single seif (seif echad), yet dense, broken into seven rules. Is a woman who finds blood while urinating a nidda? It all turns on the source of the blood: blood from a wound (dam makka) in the bladder or kidney does not render impure, unlike blood from the uterine source (makor). The role of position (sitting or standing) and of the vessel (hasefel), of pain as evidence (yadayim mochichot), of the mokh bedikah, and the distinction from kidney stones (chol vechatzatz). A medical subject: every conclusion is settled with the Rav and the physician.
Topic: Blood found while urinating — a wound in the bladder or kidney, position and vessel, the mokh bedikah Source: שולחן ערוך יורה דעה סימן קצ״א
Compilation: הרב יוסף חיים סממה DAAT · daattorah.com
📑 Study plan
1.The text of the Mehaber and the Rama: a single seif, broken into seven rules
2.Context: why blood "with the urine" is not nidda blood
Siman 191 deals with a precise clinical situation: a woman urinates and blood comes out with her urine. Must we fear that she is a נדה (impure)? The Mehaber's (Rabbi Yossef Karo) principle is that this blood comes from a wound (makka) in the urinary tract — bladder or kidney — and not from the uterus (makor): she therefore remains טהורה (pure). The Rama (Rabbi Moshe Isserles) elaborates the gloss at length: position, the vessel, pain, the mokh bedikah and the stones. The siman has only one seif, but seven successive rules may be read in it. Let us study them one by one. A medical subject: this level explains the text; any concrete application is made with a Rav and a physician.
Rule 1 — Blood that comes out with the urine: tehora (dam makka)
A woman who urinates and from whom blood comes out with her urine — whether she urinated standing or sitting — is טהורה (pure). And even if she felt her body tremble (hirgisha gufah venizdaazaa), she need not be concerned: for it is the sensation of urination (hargashat mei ragleha), and the urine does not come from the חדר (the uterus); this blood is blood of a wound (dam makka) in the חלחולת (the urinary tract / intestine) or in the כוליא (the kidney).
The founding idea: only blood from the מקור (the uterine source) renders one a nidda. Blood that accompanies the urine does not come from there — it is a bleeding from a wound in the urinary tract. Even the הרגשה (the internal sensation of opening, which usually accompanies nidda blood) changes nothing here: it is the sensation of urination, not of a uterine flow.
Rule 2 — The Rama: sitting / standing, and the vessel (hasefel)
Rama's gloss: some say she is declared pure only if she was sitting when she urinated. If she was standing: provided she urinates in a stream (mekalachat) into the vessel and the blood is found there → טהורה; but if it trickles onto the rim of the vessel (sefat hasefel) and the blood is found there → טמאה, since the makor being narrow (hamakor tzar), [the blood] returns there and comes back out. Others say that even sitting, it is permitted only in a stream with blood inside the vessel; on the rim → טמאה, and standing, in every case → טמאה. And so is the practice (vehachi nahug).
Why do position and the stream matter? As long as the blood descends squarely in a stream into the vessel, we are certain it accompanies the urine (hence a wound). But if the blood seeps slowly onto the rim, we fear it comes from the makor (uterus) — all the more since the passage is narrow. The Rama adopts the stringent ruling: clear purity holds only sitting, in a stream, blood inside the vessel.
And this only when the blood is found in a vessel where she alone urinates — for then we know it comes from her. But if it is found in a vessel where a man and a woman both urinate → she is טהורה in every case (since we do not know whose the blood is).
The doubt acquits. If the vessel (or the toilet) is shared, the blood can no longer be attributed to this woman with certainty — it could come from another source. This safek (doubt) suffices to keep her pure in every case.
Rule 4 — The chronic case with pain: permitted (yadayim mochichot)
All this applies to blood found by chance (mikreh). But a woman who regularly sees blood in her urine and feels pain (keev) at the moment of urinating — as in the urinary ailment called [hari'n vind] — is permitted in every case, for there is here yadayim mochichot ("hands that prove," a manifest indication) that she has a wound that pains her when she urinates, and from which the blood comes out. Even if she finds blood after urinating, while wiping herself → טהורה: since she feels pain and finds the blood only after urinating, it is certainly blood of a wound.
ידים מוכיחות — literally "hands that prove": a manifest indication that establishes the cause of a fact. Here, the chronic pain when urinating proves the existence of a wound in the urinary tract — the source of the blood is therefore not the uterus.
Rule 5 — The mokh bedikah (the stringent ones) and the chazaka after three times
However, some are stringent: they permit only for a woman with a regular cycle (veset), and require a bedikah (examination). Namely: before urinating, let her examine herself well in the folds (chorin usedakin); if she finds no blood there, let her insert a clean mokh (a clean tampon) against the makor, on the inside; let her urinate and then wipe herself carefully of the urine, and remove the mokh. If it is clean → it is a great proof (hochacha gedola) that the blood does not come from the makor. And so is the practice. And if she has done this bedikah three times and found the mokh clean → she is thereafter permitted without a bedikah (outside the time of her veset), for there is a chazaka (an established presumption) that it is blood of a wound.
The mokh bedikah is a demonstration. By placing a clean tampon against the uterus before urinating, one isolates the two possible sources: if after urinating the tampon comes out clean, it is proof that the blood comes from the urinary tract and not from the makor. Repeated three times successfully, this proof becomes a chazaka that dispenses with subsequent examinations (outside the cycle period).
Rule 6 — Without pain: temea, and the dispute when blood is in the urine + on the ed
And all this applies only as long as she feels pain when urinating. But if she feels no pain and, examining herself after urinating, finds blood: if there was no blood in the urine itself → she is certainly טמאה. By contrast, if she found blood both in the urine and on the ed (the examination cloth) → a dispute (machloket): some say טמאה (they permitted only blood found within the urine itself), others say טהורה (the blood on the ed comes from a residue (tamtzit) of urine) — and one should be stringent (yesh lehachmir).
Pain remains the pivot. Without it, the missing indication tips toward stringency: blood found only upon wiping, with no blood in the urine, renders one טמאה. And even when there is blood in the urine and on the ed, the Rama rules stringently (yesh lehachmir).
And if, examining herself afterward, she finds no blood but only grains, like red sand and gravel (kartin kartin kemo chol vechatzatz adom), and the same is found in her urine → she is טהורה: for it is not blood, but sand that is normally formed in the kidneys (chol shedarko lehivaled bakelayot).
The siman closes on a clinical clarification: these "red grains like sand" are not nidda blood but kidney stones / sand. The physical nature of what is found decides the status — which, today, is a matter for medical diagnosis.
2. Context — why this blood is not nidda blood
The laws of נדה rest on a distinction of source: only blood issuing from the מקור (the uterine "source," the chadar) renders a woman impure. The whole of Siman 191 applies this principle to a case where the blood appears during urination: its most probable origin is then a wound in the urinary tract (bladder, kidney, ducts) — a דם מכה — and not the uterus.
The difficulty is that one does not see the source: one infers it. That is why the siman lists indications that make the "urinary" origin plausible or certain — position and stream, pain, the shared vessel, and above all the mokh bedikah, which physically isolates the two sources. Conversely, the absence of pain and blood found only upon wiping tip toward stringency.
The overarching question: where does the blood come from? From the makor (→ nidda) or from a makka in the urinary tract (→ tehora)? Every rule of the seif is a tool for answering this single question — and today, medical diagnosis (urologist, gynecologist) reinforces this inference, without ever replacing the Rav's ruling.
3. The key concepts of this siman
A few technical terms structure the entire siman. Mastering them is to grasp the reasoning.
מקור / חדר — The uterine source: the uterus, the only place whose blood renders one a nidda. The whole siman seeks to establish that the blood does not come from there.
דם מכה — Blood of a wound: bleeding from a lesion (here of the חלחולת, the urinary tract, or of the כוליא, the kidney). It does not render impure, since it does not come from the makor.
הרגשה — The sensation: the internal perception that usually accompanies the emission of nidda blood. The Mehaber specifies that here it is merely the sensation of urination (hargashat mei ragleha), with no value of impurity.
הספל — The vessel: the urination vessel. Its evidentiary role depends on the stream (mekalachat) — blood inside the vessel (tehora) vs on the rim (sefat hasefel) (temea) — and on whether it is shared.
ידים מוכיחות — "Hands that prove": a manifest indication. The chronic pain when urinating proves the existence of a wound, and hence the non-uterine origin of the blood.
בדיקת המוך — The mokh examination: one places a מוך נקי (clean tampon) against the makor before urinating; if it comes out clean, it is proof the blood is not uterine. Three successes → חזקה.
חול וחצץ — Sand and gravel: kidney stones / sand ("red grains"). These are not blood; their presence renders one טהורה (Rule 7).
Two reference notions in nidda:וסת (the regular cycle, which conditions certain leniencies) and חזקה (the established presumption after repetition) — both decisive in the mokh bedikah (Rule 5).
4. The table — position, stream, pain
The whole seif is summed up by crossing three variables: position, where the blood is, and the presence of pain.
Situation
Detail
Status (per the text)
Sitting, in a stream, blood inside the vessel
The Rama's clear case
🟢 טהורה
Standing, in a stream, blood inside the vessel
Permitted per the 1st view; the 2nd (and the practice) → temea
🟡 machloket → the practice: temea
Blood on the rim (sefat hasefel)
We fear a return to the makor (narrow)
🔴 טמאה
Shared vessel (man + woman)
We do not know whose the blood is
🟢 טהורה (in every case)
Chronic with pain (yadayim mochichot)
Even blood found upon wiping
🟢 טהורה (the stringent: mokh bedikah)
Without pain, blood only upon wiping
No blood in the urine
🔴 טמאה (certain)
Without pain, blood in the urine and on the ed
machloket (tamtzit)
🟡 yesh lehachmir
Grains of chol vechatzatz (stones)
It is not blood
🟢 טהורה
The logic in one sentence: the more the "urinary" origin is proven (stream into the vessel, pain, clean mokh, shared vessel, stones), the more she is tehora; the more it is doubtful (blood on the rim, without pain, upon wiping), the more one leans toward stringency. The concrete decision belongs to the Rav, with the physician's input.
5. The Taz and the Shach — the great commentators
In Yoreh De'ah, the Shulchan Aruch is always studied with its commentaries. On matters of nidda, the Taz and the Shach remain the principal nossei kelim, complemented by the specialized Acharonim (Sidrei Tahara, Chochmat Adam, Aruch haShulchan).
The Taz (ט״ז) — טורי זהב, Turei Zahav, by Rabbi David haLevi Segal (Poland, 17th century). On our siman he clarifies the sitting/standing distinction, the vessel (hasefel) and the mokh bedikah.
The Shach (ש״ך) — שפתי כהן, Siftei Kohen, by Rabbi Shabtai haCohen (Lithuania, 17th century). On this siman, his remarks extend into the Sidrei Tahara and the Chochmat Adam, which detail the conditions of the proof.
The method of the higher level: the Taz and the Shach do not repeat the Mehaber — they clarify the mechanism (why the stream, why the rim, how the mokh bedikah works) and decide the disputes of the seif. This is the subject of the Lamdan level, completed at Level 4 by the ruling of contemporary poskim on the medical angle.
The Pitchei Teshuva (פתחי תשובה) further gathers the responsa of the Acharonim on this siman — the mokh bedikah, the chronic case, the stones — and serves as the gateway to the responsa literature.
6. The Rama's gloss (הגה)
In this siman, the heart is in the Rama: the Mehaber lays down the principle in one line, and it is the Rama who unfolds the six practical rules. Let us recap his interventions.
On position and the vessel — the settled practice
Rama's gloss: וי״א דאין להתירה אלא ביושבת… ובעומדת בכל ענין טמאה, והכי נהוג — "some permit only when sitting… and standing, in every case, temea; and so is the practice." Clear purity presupposes: sitting, in a stream, blood inside the vessel.
On the shared vessel
אבל אם נמצא בספל שאיש ואשה מטילין שם מים — טהורה בכל ענין — "but if it is found in a vessel where a man and a woman urinate, she is tehora in every case": the doubt about the origin of the blood acquits her.
On the chronic case with pain
אשה שרגילה לראות דם… ומרגשת כאב… יש להתיר בכל ענין, דהא איכא ידים מוכיחות — "a woman who regularly sees blood and feels pain: she is permitted in every case, for there are yadayim mochichot": the pain proves the wound.
On the mokh bedikah
אך יש מחמירין… להצריכה בדיקה… תכניס מוך נקי על המקור… אם נקיה היא הוכחה גדולה… והכי נהוג — "but some are stringent and require a bedikah: insert a clean tampon against the makor… if it is clean, a great proof… and so is the practice." Three successes → חזקה.
On blood without pain and the stones
Without pain, blood only upon wiping → ודאי טמאה; blood in the urine and on the ed → יש להחמיר. But grains כמו חול וחצץ אדום (stones) → טהורה, for it is not blood.
The Rama builds a ladder of proof: from the clearest case (sitting, stream, pain, clean mokh, shared vessel, stones → tehora) to the most doubtful (blood on the rim, without pain, upon wiping → temea / be stringent).
7. Dam makka vs dam hamakor — what the bedikah comes to prove
The conceptual heart of the siman lies in one opposition: does the blood come from a wound (makka) in the urinary tract, or from the uterine source (makor)?
The הרגשה does not decide on its own: the sensation of urination resembles that of a flow, but does not signal a uterine origin. That is why the siman seeks other proofs: position and stream (does the blood descend squarely with the urine?), pain (yadayim mochichot of a wound), and above all the mokh bedikah, which physically separates the two sources.
Indication
Toward dam makka (tehora)
Toward dam hamakor (temea)
Position / stream
Sitting, in a stream, blood in the vessel
Standing, or blood on the rim (sefat hasefel)
Pain
Present (yadayim mochichot)
Absent
Mokh bedikah
Tampon comes out clean (×3 → chazaka)
Tampon soiled
Nature of the "blood"
Grains / sand (chol vechatzatz)
Actual blood
The mokh bedikah is the decisive instrument: by placing a clean tampon against the uterus before urination, an uncertain inference is turned into direct proof. Repeated three times successfully, it founds a חזקה that dispenses with later examinations. Today, medical examination (cytology, imaging, urology) confirms the nature and source of the bleeding — a support for the Rav, never a substitute for his ruling.
8. Modern practical cases
How do these rules apply today? Here are four common clinical situations. A medical and halachic subject at once: every conclusion is settled with the Rav and a physician (urologist or gynecologist).
Case 1 — Blood in the urine (hematuria) / cystitis / urinary infection
A woman notices blood in her urine, sometimes with burning (cystitis, infection). This is first a medical question: a urologist identifies the cause (inflammation, a wound of the bladder or urinary tract) — which corresponds to the דם מכה בחלחולת of the siman. Halachically, the mokh bedikah serves to prove that the blood is not uterine (Rule 5). Conclusion: consult the Rav and the physician (urologist); the medical diagnosis illuminates the ruling, without replacing it.
Case 2 — Kidney stones (chol / chatzatz)
The woman finds reddish, sandy "grains" rather than actual blood — these are kidney stones or sand, exactly as in Rule 7 (חול שדרכו להוולד בכליות). This is not nidda blood. The diagnosis (analysis, imaging) confirms the lithiasic nature. Conclusion: consult the Rav and the physician to establish that these are indeed stones and not bleeding.
Case 3 — Pain as evidence (yadayim mochichot)
When urinary bleeding is accompanied by recurrent pain when urinating, this pain is, in the siman, a manifest indication (ידים מוכיחות) of a wound — hence of non-uterine blood (Rule 4). Medically, the pain points toward cystitis, a stone, a lesion of the urinary tract. Conclusion: describe the pain precisely to the Rav and the physician, who together assess its bearing.
Case 4 — Shared toilet / vessel
Blood found in a toilet or vessel also used by others cannot be attributed with certainty to this woman: Rule 3 (ספל שאיש ואשה מטילין שם) then keeps her tehora in every case. The facts must still be verified. Conclusion: present the exact situation to the Rav, and to the physician for anything touching health.
The thread running through the four cases: first, identify the source of the blood. The siman provides the indications (stream, pain, mokh, vessel, stones); modern medicine provides the diagnosis. But the decision of impurity or purity always belongs to the Rav, informed by the physician. Never decide a medical case on your own.
9. Synthesis of Siman 191
The essence of Siman 191 in a few sentences:
Blood coming out with the urine → טהורה: it is a דם מכה (a wound of the bladder or kidney), not from the makor — even with הרגשה (Rule 1).
The Rama: clear purity sitting, in a stream, blood in the vessel; on the rim (sefat hasefel) or standing → temea (vehachi nahug) (Rule 2).
A shared vessel for man/woman → טהורה in every case (Rule 3).
A chronic case with pain → permitted in every case (ידים מוכיחות), even blood found upon wiping (Rule 4).
The stringent: the mokh bedikah (a clean tampon against the makor); three successes → חזקה (Rule 5).
Without pain → temea; blood in the urine and on the ed → dispute, yesh lehachmir (Rule 6).
Grains of chol vechatzatz (kidney stones) → טהורה, it is not blood (Rule 7).
Memory table
Situation
Status
Blood with the urine, sitting, in a stream into the vessel
🟢 טהורה (dam makka)
Blood on the rim of the vessel / standing
🔴 טמאה (vehachi nahug)
Shared vessel for man/woman
🟢 טהורה (in every case)
Chronic with pain
🟢 טהורה (yadayim mochichot; mokh bedikah)
Without pain, blood only upon wiping
🔴 טמאה
Grains like chol vechatzatz (stones)
🟢 טהורה
Comprehension questions
Check your understanding:
Why does blood coming out with the urine not render one a nidda? What is a דם מכה?
What difference do position (sitting / standing) and urinating in a stream (mekalachat) make? Why does blood on the rim (sefat hasefel) render one temea?
Why does a shared vessel between a man and a woman render one tehora in every case?
What are the ידים מוכיחות? What role does pain play (Rule 4)?
Describe the mokh bedikah. What does a clean tampon prove? How many times to establish a חזקה?
Without pain, what is the status? And the dispute when there is blood in the urine and on the ed (tamtzit)?
What are the חול וחצץ? Why do they render one tehora (Rule 7)?
To whom does one turn, in all these medical cases, to decide concretely?
To go further
If you want to deepen this siman:
📚 Level 2 — Lamdan: the pilpul — dam makka in the chalcholet/kuliya vs dam hamakor, the dispute over standing/sitting and the return to the narrow makor, the yesod of yadayim mochichot and chezkat makka, anchored in the sugyot of Nidda
✨ Level 3 — Synthesis: the comparative tables (position, stream, pain, bedikah) and quick memorization of the seven rules
⚖️ Level 4 — Daat HaRav (Chabad) & Halacha lema'asse: the practical ruling (Beit Yossef, Rama, Shach, Taz, Sidrei Tahara, Chochmat Adam, Aruch haShulchan, Taharat haBayit, Shevet haLevi) and the medical angle (Nishmat Avraham)
The sources for this level can be consulted on Sefaria: