There's a famous minority opinion of Rambam that, Biblically, the nidda and zava cycle is continuous--7-11-7-11-7 days ad infinitum, and that most Rishonim argue on him and hold the cycle is 7-11 days (and the next seven days begin with the next period). Chatam Sofer says that Rambam's opinion is rejected in favor of the more accepted opinion (Responsa Yoreh Deah 143; thanks Robert).

Which Rabbis (rishonim and achronim) agree (or partially agree) with Rambam and who completely rejects his opinion?

(I would imagine that because we are dealing with a possible issur kareit the Rambam's position has not been completely rejected).

  • We aren't really dealing with an Issur Kareis or any practical difference, since we always keep the Chumros of Zava.
    – HaLeiVi
    Commented Jun 18, 2015 at 16:43
  • Yes, but if Rabbis want to be lenient for extenuating cases, it will be easier to rule that way if Rambam is a rejected opinion. Commented Jun 18, 2015 at 16:44
  • I never heard of bypassing the שבעה נקיים. And, for שעת הדחק we'd pick the lighter Shitos regardless.
    – HaLeiVi
    Commented Jun 18, 2015 at 16:50
  • @HaLeiVi: Haven't heard yet.... We live in crazy times my friend. Commented Jun 18, 2015 at 17:02
  • 1
    @HaLeiVi: Anyway, psak is not exactly the issue. My main concern is knowing what is kareit and what is not. Commented Jun 18, 2015 at 17:05

4 Answers 4


The Aruch Hashulchan (קפג-יב) writes that the Rambams opinion was really also the opinion of Rav Shreira Gaon printed in the Medrash Tanchuma the end of Parshas Metzora (אות ח)

  • According to this understanding, how would the Rambam understand all those Sugyos of Vestos? The Gemara gives options for someone who messed up the counting. According to this, there's no hope.
    – HaLeiVi
    Commented Jun 18, 2015 at 16:47
  • @HaLeiVi see the Aruch Hashulchan that deals with all the questions facing the Rambam. Commented Jun 18, 2015 at 17:27

Rambam's position is rejected by all other Rishonim. The position of the other Rishonim is pretty well summarized by the Sefer HaChinuch which you can read here about half way down.

Regarding the Chatam Sofer, he says:

אי אפשר לעשות להרמב"ם אפילו סניף בעלמא כי שיטתו דחויה, ולא מצאנו ידינו ורגלינו ברוב הסוגיות

So yes, Chatam Sofer rejected Rambam's position.

This is in his responsa, Yoreh Deah, קמג

However, many modern Rabanim are stringent when dealing with issues such as early immersion due to IVF and similar issues, because they feel Rambam's position needs to be considered, and that basically no one can never know for sure if they are niddah or zavah under Rambam's method. One example I'm aware of is Rav Binyamin Lau who I've read is stringent due to Rambam's position.

  • Comments are not for extended discussion; this conversation has been moved to chat. Commented Jun 23, 2015 at 2:38
  • Part of this sugya can be about sfek sfeika. I have seen a quote from Rav Ovadya Yosef who holds that sfek sfeika is mutar even by a kareit. I do not understand that, because if you are dealing with a possible kareit that can happen to a person due to inadvertent sin, then how can you be lenient even by 100 doubts (kareit may apply because the chatat korbon may be in place of kereit)? Chacham Ovadya may hold that a shogeg doesn't get kareit. Commented Apr 26, 2016 at 20:20
  • @Emetv'Shalom In what way? Rambam's opinion is categorically rejected by all other Rishonim, and from a modern point of view his position makes no sense unless you assume that he's making a hishtaneh ha'teva argument and saying that women used to have perfectly regular 7-11 cycles, but that at some point nature changed. In fact that's how I read it personally. Regarding sfek sfeika, I could see that according to "sfek d'oriyta l'hachmir, sfek d'rabinan l'hakel" once you get to sfek sfeika you've went beyond the bounds of the rule and sfek sfeika is always like d'rabinan and you're lenient Commented Apr 27, 2016 at 18:26
  • I thought Rambam's position was that he is reading into the wording of the gemara which says that zava days are between nidda and nidda and is not connected to logic. As for the safek 'rule,' if there is a spiritual reality called kareit, then it will happen no matter what you rule. The only answer that satisfies me is eilu v'eilu, but perhaps the Rambam is really right about the cycle somehow. It is extremely unlikely, but it is still a possibility. Commented Apr 27, 2016 at 23:47

The Shach Yoreh De'ah 183:4 understood the opinion of the Levush to be like the Rambam. However, the Shach himself notes that there is a contradiction within the Levush on this point, and many later Acharonim dispute the Shach's understanding of the Levush (Toras Hashelomim, Mekor Mayim Chaim, and others).

The Meromei Sadeh to Niddah 39b s.v. פרש"י commenting on Rashi s.v. וקתני אסורה suggests that Rashi actually holds like the Rambam.


In addition to opinions mentioned in the other answers, the Semag (Lavin 111) accords with the Rambam:

והזהר בשתי שמות אלו שהן ימי נדתה וימי זיבתה כל ימי האשה מיום שנקבע לה ווסת עד שתמות או עד שיעקור הווסת ליום אחר תספור לעולם שבעה מתחילת יום הווסת ואחריהם אחד עשר יום ואחריהם שבעה ואחריהם י"א יום ותזהר במניין כדי שתדע בעת שתראה דם אם בימי נדה ראתה או בימי זיבה שכל ימיה של אשה כך הם שבעה ימי הנדה ואחד עשר יום שהן ימי זיבה אא"כ הפסיקה הלידה כמו שמוכיח במסכת נדה (לח, א ע"ש)

The Rashba (Nidda 54a, "סבור הרב ז"ל דלעולם חוזרת לפתח נדתה מי"ח לי"ח בין רואה בין אינה רואה וגם הרמב"ם ז"ל כן כתב ואי אפשר להעמיד שמועתינו לדבריהם כלל") cites Rabbeinu Chananel as also having this position (and this has subsequently been confirmed by a manuscript of Rabbeinu Chananel on Nidda from the Cairo Geniza,1 where he follows the wording of R' Sh'rira Gaon).

1 See page רצג here

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