Pearls are formed within the shells of specific mollusks, primarily oysters and mussels. When an irritant, such as a grain of sand or parasite, enters the mollusk's soft tissue, the organism initiates a defense mechanism. It secretes nacre (mother-of-pearl), composed primarily of calcium carbonate and organic compounds. The nacre accumulates in concentric layers around the irritant, gradually forming a pearl. This process requires several months to years, depending on factors such as mollusk species and environmental conditions.

Pearls have been used in Traditional Chinese Medicine for millennia. Ancient physicians documented their applications and effects in classical medical texts. Through continuous practice and knowledge transmission, pearls earned esteemed status in traditional medicine, leading to their inclusion among the "Nine Elite Herbs."

In summary, pearls ' unique composition with demonstrated medicinal properties, combined with profound cultural and historical significance, earned them recognition as one of the Nine Elite Herbs in traditional Chinese medicine. Modern scientific research continues to investigate and validate the precise pharmacological mechanisms and efficacy of pearls .