Can I add fresh elderberries or rosehips to homemade kombucha?
See the below, but basically, no raw or unripe elderberries. Also, if there is any chance of the rosehips being chewed, or cut open, remove the seeds (rose seeds are a traditional source of itching powder).

From http://elderberries.ning.com/forum/topics/elderberry-faq-what-they-are:


  Can I eat the berries raw?
  Some say that as long as they’re ripe you can eat them uncooked in small quantities, but most sources maintain that berries need to be cooked to fully remove all the toxins. (In addition, elderberries are really quite bitter until they’ve been sweetened with sugar or honey.) Again, as the non-doctor giving advice, I’d err on the side of caution and make sure your elderberries are washed and cooked. On the plus side, I’m collecting quite a few elderberry recipes here, so there should be no shortage of ways to cook them.


From http://homecooking.about.com/library/archive/blrosehips.htm:


  Anyone using rose hips for cooking should remove all the seeds. They are covered with sliver-hairs that, when ingested, irritate the digestive system and cause what the aboriginal people call "itchy bottom disease."
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