Regarding a woman who was attending to her needs [i.e. urinating] and she saw blood, Rabbi Meir says: if she was standing she is impure, but if she was sitting she is pure. Rabbi Yose says: in either case she is pure.

Regarding a man and a woman who attended to their needs into a bowl, if blood was found on the water, Rabbi Yose considers it pure, and Rabbi Shimon considers it impure, since it is not usual for a man to discharge blood; rather the presumption regarding blood is that it came from the woman.

If a woman lent her robe to a gentile woman or to a niddah [a female who has menstrual discharges which render her impure], she may attribute [any bloodstain] to her. If three women wore the same robe or sat on the same bench, and blood was then found on it, they are all impure. If they sat on a stone bench or on [a ledge in] the colonnade of a bath house, Rabbi Nechemia considers them pure, for Rabbi Nechemia would say: Anything that cannot be rendered impure cannot retain a stain.

If three women were sleeping in one bed and blood was found under one of them, they are all impure. If one of them examined [herself] and was found to be impure, she is impure and the other two are pure; and [even if none of them examined] they may attribute to one another [if there is any reason to assume one of them is more or less fit to see blood]. And if none of them are fit to see [blood, i.e. if they were virgins or pregnant, etc.], we view all of them as though they are fit [to see blood].

If three women were sleeping in one bed and blood was found under the middle one, they are all impure. If [it was found] under the one on the inside [i.e. if the bed was beside a wall], the two inner ones are impure and the one on the outside is pure. If [it was found] under the outside one, the two outside ones are impure and the one on the inside is pure. Rabbi Yehuda said: when is this the case? When they passed by way of the foot of the bed; but if the three of them passed by way of climbing on [from the side], they are all impure. If one of them examined [herself] and was found to be pure, she is pure and the other two are impure. If two of them examined and found [themselves] to be pure, they are pure and the third one is impure. If the three of them [examined] and found themselves to be pure, they are all impure. To what is this comparable? To an impure mound [of stones containing a corpse] which became mixed among two pure mounds. If one of them was examined and found to be pure, it is pure and the other two are impure. If two of them were [examined and] found to be pure, they are pure and the third is impure. If the three of them were [examined and] found to be pure, they are all impure, according Rabbi Meir, for Rabbi Meir would say: Anything which is presumed to be impure remains in its impurity until the location of the impurity becomes known in certainty. And the Sages say: one should examine [the mounds to search for the corpse] until one reaches a rock or virgin soil [underneath them, indicating the absence of impurity].

Seven compounds remove a [blood] stain [and can thereby be used to test whether a stain is blood]: bland saliva, bean water, urine, lye, soap, cimolite [a type of clay used for cleaning], and potash [a potassium compound used for soap]. If one immersed it [a stained item] and prepared pure items upon it, and passed these seven compounds over it and the stain did not pass, it is thereby dye, the pure items remain pure, and one does not need to immerse it. If it did pass, or if it faded, it is thereby a [blood] stain, and the pure items are impure, and one must immerse it.

What is bland saliva? That which [is from someone who] has not tasted anything [that day]. Bean water? Ground up grits of beans that had split apart [in water]. Urine? That which has soured. And one must scrub it three times for each and every one. If one passed these [compounds over the stain] out of order [i.e. not in the order in which they appear in the Mishna], or if one passed all seven of them over it at once, [it is as though] he has done nothing.

Any woman who has regular [indicative symptoms around her] cycles, her hour [of discovering menstrual blood] is sufficient for her [to reckon her period of impurity from that moment]. The following are considered regular [indicative symptoms around her] cycles: if she yawns [around the time that she menstruates], or if she sneezes, or if she has a [painful] feeling in her stomach or in her lower abdomen, or if she has a discharge, or if she is seized by a kind of chill [i.e. shivers or goosebumps], or other similar symptoms. Any woman who has established three occurrences [of any one these symptoms], this is thereby a regular [indicative symptom for her] cycle.

If she is accustomed to regularly seeing [blood] at the beginning of her regular [experiencing of indicative symptoms of her] cycle, all pure items which she handled during her regular [indicative symptoms of her] cycle are impure. If [she is accustomed to regularly seeing blood] at the end of her regular [experiencing of indicative symptoms of her] cycle, all pure items which she handled during her regular [indicative symptoms of her] cycle are pure. Rabbi Yose says: even days and hours can be [indications of] regular cycles [i.e. if she regularly sees blood on certain days or hours, she can establish a regular cycle based on that]. If [for instance] she is accustomed to regularly seeing [blood] at sunrise, she is not forbidden [to her husband as a niddah on the day of her regular cycle] until sunrise. Rabbi Yehuda says: the entire day is hers [i.e. if she did not see blood after sunrise, she is permitted to her husband for the entire day, but not the night before].

If she is accustomed to regularly seeing [blood] on the fifteenth day [of the month], and she changed to seeing on the twentieth day, this [day] and that are forbidden [for her to have relations with her husband]. If she changed to [seeing on] the twentieth day twice, this [day] and that are forbidden. If she changed to [seeing on] the twentieth day three times, the fifteenth becomes permitted, and she has established the twentieth for herself [as the time of her regular cycle], for a woman can only establish a regular cycle for herself if she establishes it three times. And she can only be purified from [becoming impure on] her regular cycle once she is uprooted from it [i.e. it does not occur as expected] three times.

Women, with regard to their virginal blood, are like grapevines. There are vines whose wine is red, and there are vines whose wine is black, and there are vines whose wine is abundant, and there are vines whose wine is meager. Rabbi Yehuda says: every vine has wine in it; and that which does not have wine in it is dried up [i.e. infertile].