Blackberries are an obvious food source but they also have medicinal value. The berries are packed with antioxidants and vitamins but you can also eat the leaves and roots. The leaves and roots can help treat diarrhea and they also act as an anti inflammatory so they can be chewed to relieve sores or cuts in the mouth. Be careful when touching the stem as this plant has thorns. There are no poisonous look a likes.