Simcha BabaevBy Torah law a woman becomes a niddah only through bleeding accompanied by a hargashah. The practical halachah is broader. So what are the other situations that make a woman a niddah?
Substantial bleeding — even without a hargashah
A woman who experiences actual bleeding — a flow rather than a drop — is a niddah even if she felt nothing. That is why a woman having her ordinary monthly period becomes a niddah without any hargashah. So too a woman who saw blood emerge from her body becomes a niddah, unless the blood can be attributed to another source (a wound, a nosebleed and the like).
The stain — a rabbinic decree
Chazal added a decree: under certain circumstances a stain also renders a woman temei'ah (Niddah 58–59). This is rabbinic rather than Torah law, which is why the criteria are precise and worth knowing well.
For a stain to render a woman a niddah, five conditions must hold together.
The five conditions of a stain that renders a woman temei'ah
1. Size — larger than a gris
The stain must be larger than a "gris." What is a gris? A circle whose diameter is 21 mm according to the lenient view (Rav Chaim Na'eh) and 13 mm according to the stringent one. Each woman should clarify with her rav which view she follows.
Stains are often not perfect circles, and their size is hard to judge precisely. In that case, ask.
2. Color — a color that renders temei'ah
The stain must be a color that "renders temei'ah" (Niddah 19a).
- Red and black are problematic colors.
- White, green, blue and pale yellow are not.
- Any other shade requires a posek's assessment, if all the other criteria are met.
- Some poskim (such as Rav Henkin zt"l) always accept beige and light brown with no tendency toward red.
3. Surface — one that can receive tum'ah
The stain must be on a surface capable of receiving tum'ah. Anything attached to the ground, such as a toilet or a bathtub, cannot. Disposable items usually cannot either.
The status of panty liners, pads and toilet paper is a machloket. Each woman should clarify with her rav how to proceed.
4. Background color — a white surface
The stain must be on a white surface, or on the body itself. A stain found on colored fabric does not render a woman temei'ah (Niddah 61b).
For this reason it is strongly recommended that a woman wear colored underwear throughout the days she is tehorah.
5. No other source to attribute it to
The stain cannot be attributable to another cause (Niddah 58–59). If a woman has a wound, or handled a substance of a similar color, that is relevant information when asking a halachic question.
A fine distinction — stain or bleeding?
Light bleeding and heavy staining can be hard to tell apart. A woman who is unsure should ask a posek.
A note on the stringent view
Some poskim hold that even a stain on a colored surface, or on a surface that cannot receive tum'ah, always requires a question if it is larger than a gris. Each woman should clarify her rav's position so she knows whether she must ask about every stain.
Practical halachah
The laws of ketamim carry a great many details. So here, as throughout the laws of niddah, a woman in doubt should ask rather than choose to be stringent on her own. Stringency without halachic guidance can turn into stringency in other areas.