Medicine From Oyster Shell
I bought a prostrate relief dietary supplement and I see it contains calcium derived from oyster shell powder. Am I allowed to take it?
The Aish Rabbi Replies
Yes, it is permissible and we wish you a speedy recovery.
In greater detail, in general the Torah forbade only edible parts of non-kosher animals – not the claws, horns, shells etc. The reason is that such animal parts are completely inedible and not considered “food” at all. (See Leviticus 11:8 which only forbids the flesh of non-kosher animals (see Rashi there citing Sifra 4:8).) Note, however, that many types of bones and shells – in particular of shellfish – do impart some taste and are forbidden. Also, the “sinew of the thigh” (gid ha’nasheh) is one exception to this rule, and is explicitly forbidden by the Torah even though it has no taste.
Even so, there is still a potential issue. When an inedible shell is made into an edible product, we preferably should not eat it. Although technically not forbidden, it still is a product of a non-kosher animal so possibly causes the same spiritual damage as non-kosher food. Even this doesn’t really apply if the shell was only made into a pill form – which isn’t edible at all (even though we swallow them). Nevertheless, some are stringent beyond the letter of the law that if they are healthy and just seeking a supplement they would opt for pills with kosher ingredients and not even derivatives of inedible non-kosher. (By contrast, one who has a health issue does not have to be strict by pills at all and only should preferably try to find a kosher alternative if the medicine is tasty.)
See also this response for a more detailed summary of the laws of non-kosher medicines.
(Sources: Sefer HaChinuch 74; Mishnah L’Melech, Yesodei HaTorah 5:8; K’sav Sofer O.C. 111; Achiezer Y.D. 11; Tzitz Eliezer X 25:20; Minchas Yitzchak IX 79.)