Some herbs can be a diuretic but definetely not all. Some may actually do the opposite. Why dont you get a book about different herbs, it explains what they do. Just remember that the amount of herbs you are getting in a tea isn't all that much so usually you would have to be drinking a good amount of the tea. Too much chamomile tea or other flowery teas actually may cause constipation. If there is a specific tea that you like thats probably a sign that its good for you. I wouldn't just drink a lot of peppermint tea tho cause you hear its good for digestion becuase for some people it may actually not be or may not be some of the time. For some, ginger may be a better choice. Sometimes ginger may be good in the mornings and peppermint at night. You have to see how the herbs work fo you. If you have something with spices for dinner, it may be better to have some cooling peppermint tea rather than ginger tea which has the same type of warming properties as the spices in your meal.