Sold in dried form, ba wang hua (dried night-blooming cereus) is a flower that is used in traditional Chinese medicine to help with detoxification and reduce lung inflammation. The flowers are usually used in soups. When boiled, they add a sweet and slight thickening effect to soup. 

(tnp.sq)

From the manufacturer: 

This is the flower of the cactus family. The taste is sweet; it is slightly cold in nature. It is used for lung-heat cough, pulmonary tuberculosis, scrofula. It enters the Lung meridian. It is frequently cooked in soups. 

This recipe is used to clear lung inflammation and enhance immunity. https://www.tnp.sg/lifestyle/hed-chef/boost-your-immunity-ba-wang-hua-and-pork-rib-soup

Bawang Flower Pork Soup

• 1.8 liters of water (for blanching)
• 2 pork bones (500g), cracked into two
• 500g spare ribs (cut into 7cm by 8cm pieces)
• 3.8 liters of water
• 100g ba wang hua, well-rinsed
• 10 small red dates (17g)
• 1 honey date (20g)
• 4 chilled figs (60g)
• 20g nan bei xing (Chinese apricot kernels)
• 1 heaping tsp salt

1. Bring 1.8 liters of water to a boil in a pot. Blanch the pork bones and spare ribs until there is no visible blood.
2. Discard the water, rinse the pork bones and spare ribs and set aside.
3. Bring 3.8 liters of water to a boil in a clean pot. Place the blanched pork bones and spare ribs inside.
4. Add the ba wang hua, red dates, honey date, figs and nan bei xing.
5. Cover and bring to a boil. Then simmer covered for 1 1/2 hours.
6. Season with salt. Stir well and cover for five minutes.
7. Turn off the heat and serve.