Can Dogs Eat Rowan Berries?

Rowan berries, often seen on ornamental mountain ash trees in gardens and streets, contain parasorbic acid in their raw state, which is exactly why the traditional way people use rowan berries is as a cooked jelly or jam rather than eating them fresh - the cooking process breaks down most of the irritant compound. A dog snacking on fallen raw rowan berries during a walk is getting exposure to that uncooked, more irritating form of the fruit, which typically causes a fairly standard bout of digestive upset rather than anything more severe. This puts rowan berries at the milder end of the toxic-berry spectrum compared to something like yew or holly, though a genuinely large quantity eaten in one sitting can still cause a meaningful reaction. Most cases settle with monitoring alone, but a large amount or persistent symptoms are worth checking with your vet.