Children’s ability to identify common plants is a necessary prerequisite for learning botany. However, recent work has shown that children lack positive attitudes toward plants and are unable to identify them. We examined children’s (aged 10-17) ability to discriminate between common toxic and non-toxic plants and their mature fruits presented in a colourful PowerPoint presentation. We found that toxic plants were less well known than plants with edible fruits and those younger children were more willing to consume toxic fruits than older children. Children abilities to distinguish toxic and non-toxic plants did not increase with age suggesting that school does not play the primary role in building children’s knowledge about toxic plants. This study supports the idea that children’s knowledge about plants is limited and more effort should be dedicated to teaching about toxic plants that are often harmful especially to inexperienced children.