If a sheet is made out of a cotton–blend, when it is part cotton and part synthetic – is it still considered a natural fiber? Must there be a certain ratio of synthetic fiber to natural fiber for it to be considered a synthetic material?
Thank you for your question.
There is a difference of opinion regarding the status of synthetic fabrics with respect to tum'ah and taharah (ritual purity). Presumably, a fabric's status would depend on the majority of its fibers. But any practical questions should be brought with specifics to a halachic authority.
If you are purchasing sheets, we suggest purchasing colored sheets for non-niddah times, since stains on colored surfaces are generally treated leniently, regardless of the fabric. (See our article on stains, "Ketamim", for more details.)
If you have a practical question arising from a stain on a white sheet (as above, stains on colored sheets are generally treated leniently), please contact your local halachic authority or get back to us with details.
This internet service does not preclude, override or replace the psak of any rabbinical authority. It is the responsibility of the questioner to inform us of any previous consultation or ruling. As even slight variation in circumstances may have Halachic consequences, views expressed concerning one case may not be applied to other, seemingly similar cases.
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The Nishmat Women's Health and Halacha is a public service of Nishmat, The Jeanie Schottenstein Center for Advanced Torah Study for Women. This project and others like it are made possible by contributions from people like you. If you have benefitted from the service, and wish to enable us to help others, click here to donate.