Are Mountain Ash berries poisonous

Answer 1

According to an article by Shelly Garner that is quoted on the site http://www.gwenshealinggarden.ca/Article.Poisonous_Plants_Outdoors.htm -- the seeds of the Mountain Ash contain cyanide-producing compounds. However, the article continues on saying that "It's important to note here that Chokecherries and Mountain Ash berries can be made into a jelly, as the seeds will be thrown away after the juice is extracted."