Hawthorn Fruit (Shan Zha)

Crataegus monogyna, known as common hawthorn or single-seeded hawthorn, is a species of hawthorn native to Europe, northwest Africa and western Asia. It has been introduced in many other parts of the world where it is an invasive weed. Other common names include may, mayblossom, maythorn, quickthorn, whitethorn, motherdie, and haw. This species is one of several that have been referred to as Crataegus oxyacantha, a name that has been rejected by the botanical community as too ambiguous.
Medicinal use

Crataegus monogyna is one of the most common species used as the "hawthorn" of traditional herbalism, which is of considerable interest for treating cardiac insufficiency by evidence-based medicine. The plant parts used medicinally are usually sprigs with both leaves and flowers, or alternatively the fruit. Several species of Crataegus have both traditional and modern medicinal uses. It is a good source of antioxidant phytochemicals,especially extracts of hawthorn leaves with flowers. (source wiki)

Author's Input:
The herbalist informed me that Shan Zha has been clinically shown to be a cardio-tonic, such as lowering of cholesterol, lowering of blood pressure, and widens the coronary arteries.  Chinese use these berries to make sweets such as jams and candies.  Actually, a friend of mine is taking a diet tea that is made from Shan Zha and she said it's been helping her visit the bathroom more often.  I assume that it means that she is pooping out all the bad stuff :D.  I was curious, I tried the tea it has a faint sweet flavor.  The tea was not over powering, it was kind of bland to say the least.