Objective:To compare and analyze the medication patterns for adult and children diarrhea from Erxu Mingyi Lei’an. Methods:The cases and formula prescriptions on adult and children diarrhea were recorded from Erxu Mingyi Lei ' an. The data was analyzed and compared between adult and children by the Ancient and Modern Medical Records Cloud Platform (V 2.1), including frequency statistics, association rule analysis, drug pair analysis, efficacy statistics, drug taste tropism statistics, and cluster analysis. Results:A total of 456 prescriptions of adult diarrhea were abstracted, involving 360 drugs, and the top 5 drugs were Poria, Atractylodis Macrocephalae Rhizoma, Citri Reticulatae Pericarpium, Paeoniae Radix Alba and Aucklandiae Radix. The Atractylodis Macrocephalae Rhizoma paired with Poria, Citri Reticulatae Pericarpium with Poria, Citri Reticulatae Pericarpium with Atractylodis Macrocephalae Rhizoma, and Paeoniae Radix Alba with Atractylodis Macrocephalae Rhizoma were commonly used in the treatment of adult diarrhea. Citri Reticulatae Pericarpium, Atractylodis Macrocephalae Rhizoma and Poria were the core drugs for adult diarrhea. There were 111 prescriptions for pediatric diarrhea, involving 180 drugs, and the top 5 were Atractylodis Macrocephalae Rhizoma, Poria, Paeoniae Radix Alba, Glycyrrhizae Radix et Rhizoma, and Nelumbinis Folium. The Poria paired with Atractylodis Macrocephalae Rhizoma, Atractylodis Macrocephalae Rhizoma with Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle, and Aconiti Lateralis Radix Praeparata with Atractylodis Macrocephalae Rhizoma were commonly used in the treatment of diarrhea in children. The Atractylodis Macrocephalae Rhizoma, Poria and Aconiti Lateralis Radix Praeparata were the core drugs for children diarrhea. The main charateristics of drugswas warm type, sweet taste, and the main meridian belongs to spleen, followed by stomach and lung meridians. The use of carbided drugs in adults were significantly higher than children. Conclusions:The Erxu Mingyi Lei’an forcused the treatment of invigorating the spleen qi, where the adult formular often matches the drugs of drying dampness and invigorating the spleen, aromatizing dampness, slight infiltration and eliminating dampness, while the children formular often matches the drugs of warming the Yang and warming the Yang. Many kinds of carbonaceous drugs can be used in the treatment of adult diarrhea, but they should be used with caution in the treatment of children.