The proper procedure for decocting mother of pearl is to break it up, then soak it, then decoct it first, followed by decocting it with other medicines, and finally pouring out the juice. Mother-of-pearl is the shell of the mussel family of mussels, triangular sail mussel, pleated crown mussel, or pearl mussel family of mussels, Marsyllus pericarpus. It is salty in taste and cold in nature. It belongs to the liver and heart meridians. It can calm the liver and subdue yang (suppressing the rising of too much yang qi in the liver), tranquilize the mind and calm fright, brighten the eyes and reduce cataracts (improving vision and blurring of vision). It is used for headache and dizziness, palpitation and insomnia, redness and cataract of the eyes, and blurred vision. Mother-of-pearl is salty and cold, belonging to the product of sinking, so it should be used with caution for those who have deficiency of spleen and stomach (weak and cold spleen and stomach), and those who have deficiency of qi and sinking; pregnant women should be cautious in using it. Patients are advised to use the medicine under the guidance of a doctor.