Description: Another medicinal Chinese soup from Grace Young's The Wisdom Of The Chinese Kitchen.It is naturally high in Vitamin C and is used to fight colds and the flu.The sweet potatoes start to dissolve in the broth and sweeten it ;otherwise this is a really bland soup,though I find it's simplicity a bit refreshing if you are already sick.For medicinal purposes the tradition is that the soup be cooked a full 3 hours.It actually tastes better if you only cook it for about 1 hour though.You could add small bits of pork and a touch of salt to make it more flavourful.