Elderberries are full of wonderful. They are rich in vitamin C, full of antioxidants, flavinoides, vitamin A&B plus a whole heap of other things. Which is why they have been used medicinal for hundreds of years and why they make such a fantastic winter cough syrup.
You find them on Elder tree's just as the seasons are starting to change from Summer to Autumn (the spring/summer flowers of the elder can also be harvested). The tree's are very common in the wild and are often found along pathways or if you're lucky you may have one in your garden.
Making the cough syrup is really easy and you don't need a massive amount of berries. I don't have a specific recipe I stick too. It all depends how much juice I get out of the elderberries and I also tend to make it in small batches.