Is eating olive pits a problem?
I'd avoid this practice.


  The olive pit husk is very hard and should not be eaten, however, as it is indigestible and might injure the intestinal wall if sharp edges are present.  Also, do not chew the husk, as it is so hard it could break a tooth. Swallowing the husk is also a bad idea, as it has sharp ends that could be dangerous.  It is also quite indigestible and will come out just as it went in. (source)