Objective: To analyze the composition principles in traditional Chinese medicine (TCM) prescriptions for postpartum lochiorrhea based on the TCM Inheritance Support System (TCMISS). Method: The prescriptions for postpartum lochiorrhea in Dictionary of Chinese Medicine Prescription were collected and their composition principles were analyzed after data entry into the TCMISS. Result: Based on the analysis of 111 prescriptions including 215 herbs for postpartum lochiorrhea

there were 45 herbs with frequency≥6

48 herbal combinations with support≥10

13 association rules with support≥10 and confidence coefficient≥0.85. 18 new core combinations and 4 new prescriptions were obtained from the databases. Conclusion: In Dictionary of Chinese Medicine Prescription

herbs for enriching blood and herbs for invigorating blood circulation and eliminating stasis were used as the core compositions in prescriptions for postpartum lochiorrhea

often combined with Angelicae Sinensis Radix and Chuanxiong Rhizoma

and supplemented by herbs of reinforcing Qi

interior-warming herbs and the herbs of clearing heat and cooling blood.