In addition to the laws of niddah, the Torah details the laws of the woman with uterine bleeding outside of her expected time of menstruation. Such a woman is called a zavah, and observes laws comparable to those of a niddah (see Definition of Niddah). The Torah obligates the zavah to count seven clean days prior to becoming tehorah.
In practice, it is very difficult to distinguish between the zavah and the niddah with any certainty. (For example, there is a fundamental debate about how to identify the expected time of menstruation to determine days on which a woman could become a zavah or a niddah.) Thus, for over 1700 years, halachah has treated all women with uterine bleeding as zavot, for whom seven clean days are obligatory.
It may well be, however, that there are ways to shorten the time you are spending in niddah without resorting to medication and without abrogating halachah. You may be considering yourself niddah before it is halachically obligatory to do so and you may be making your hefsek taharah later than necessary. Not all stains make a woman niddah. Some women are able to get an earlier hefsek taharah just by taking a long soak in the bath on the day of their attempt. More important, the hefsek taharah examination need not be completely clear. Some browns may be acceptable on the hefsek taharah cloth. Additionally, not all colors invalidate the clean days. Please review our articles on stains. Please consult us or a local halachic authority before considering yourself niddah or when attempting a hefsek taharah. And please get back to us with any further questions.
One last note: if you do experience a full ten to twelve days of blood flow, it would be worthwhile to consult your physician. There are also natural methods to shorten bleeding, of which we have received anecdotal reports, such as taking alfalfa, shepherd's purse, or flax seed. (Note that shepherd's purse is a powerful herb. It may not be used during pregnancy, and its use while breastfeeding is debated – a breastfeeding mother should not try it without the guidance of a qualified professional.) Some of these reports are posted on the "How Do I…" section of our site.