Some consider it a common weed that stings and gets in the way. However, its beneficial effects have been known since the Middle Ages. Nettle contains vitamins C, B, provitamin A, magnesium, calcium, and iron. It has a positive effect on the kidneys, liver, gallbladder, helps with anemia, supports metabolism (suitable for weight reduction diets), and promotes proper bowel function. It is also useful for joint or skin problems, and it benefits the coat and nails. Nettle is suitable for dogs with allergies, diabetes, and heart conditions. Since too much of anything can be harmful and nettle is no exception, it should not be given long-term or in large quantities (it contains 20% oxalates, which in large amounts can have adverse effects on the body). The best time to harvest nettle is in spring and autumn when it is not flowering.