We normally say that you "take" medicine, even if it's a liquid. If it's a large amount of liquid medicine (a whole cup, for example), it would sound okay to say that you "drink" it. But if it's only a small amount (for example, if you measure it with a spoon), we would say that you "take" it. For soup, if you are using a spoon, we say that you are "eating" soup. If you drink it out of a cup, the same way you would drink coffee or tea, then you can say that you are "drinking" soup.