Deathberries are bright, red berries that look tasty to bears and other animals who are unaware of the danger. They are yew berries. Deathberries are very poisonous and there is no cure, unless one's fed something that lets them vomit them up.
History
Great Bear Lake
When Lusa, Toklo and Ujurak were going to the salmon river, Lusa tried to eat some deathberries by a BlackPath, not knowing they would harm her. Before she could eat the berries and meet certain death, Toklo bashed into her, hard enough to restrain her.