A few of the more common poisonous berries are woodbine, cotoneaster, pokeweed, mistletoe, holly, yew and ivy berries, according to the Children's Hospital of Philadelphia. Unfortunately, many poisonous berries resemble their benign counterparts. Many are dark blue and look similar to blueberries and huckleberries.
Juniper and yew berries are both roughly the same size and color as blueberries. Because juniper and yew are commonly grown as landscape plants, it is important to teach children not to eat them if they encounter them. Privet berries are also blue-to-black in color, and although they are only mildly poisonous to humans, they are best left alone. Elderberries are also round, bluish-purple berries that are toxic to humans and other mammals. These berries contain cyanide and should never be consumed while raw. However, the heat used in the cooking process renders the cyanide inert, which is why elderberries are often baked into pies and stirred into muffin batter. The berries of poison oak and poison ivy also resemble small blueberries and should be avoided at snack time.
American bittersweet and cotoneaster are both common woodland plants that feature yellow-to-orange berries. Many cultivated varieties of cotoneaster are used as landscaping plants and should be planted with caution in households that include children.
Homeowners should make a point of keeping a list of the botanical names of every plant that is included in their yard and garden area. Botanical names are very important because common names vary throughout different regions, making it difficult to quickly find reliable information on them.