Nishmat's Women’s Health and HalachaIn memory of Chaya Mirel bat R' Avraham

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Cotton-synthetic blend

9 February, 2009


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.


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. All health and health-related information contained within Nishmat's Women's Health & Halacha Web site is intended to be general in nature and should not be used as a substitute for consulting with your health care professional. The advice is intended to offer a basis for individuals to discuss their medical condition with their health care provider but not individual advice. Although every effort is made to ensure that the material within Nishmat's Women's Health & Halacha Web site is accurate and timely, it is provided for the convenience of the Web site user but should not be considered official. Advice for actual medical practice should be obtained from a licensed health care professional.

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