Soak peach gum in clean water for around 10 hours or overnight until it expand and softened. Then remove the black impurities and wash carefully under running water.
Add the well-cleaned peach gum into a soup pot, and add enough water (we need to simmer for quite a long time). After the contents boil, cover the lid and slow down the fire, then simmer for around 1 hour until the soup is thickened well using the slowest fire. Stir from time to time to avoid burnt bottom.
Add red dates and goji berries as well as rock sugar. Continue cooking for 10 minutes.