I have written this for educational purposes. If in doubt don’t, make certain you know your plants. This is not medical advice and should not be taken as such.
Though there are many species of Cornus (dogwood) some can be toxic and some can be edible and the leaves and berries are used. The one I am familiar with is Silky Dogwood and I make tea from the leaves and I eat the berries which are plain tasting to me.
The berries are high in quercetin.
The phytochemicals in the berries have been shown to fight cancer.