Objective To explore the relationship among the disease - syndrome - formula of type 2 diabetes.Methods Based on the clinical data of 2501 cases of type 2 diabetes

to study the relationship among the disease - syndrome - formula of type 2 diabetes by making use of association rules.Results Three formulas

Shengmai Yin （Pulse-activating Fluid）

Liuwei Dihuang Decoction （Decoction of Six Herbs Including Rehmannia）

and Sijunzi Decoction （Decoction of Four Noble Herbs）

were selected from 122 ones to analyze the relationship between the formula and symptoms. The occurrence of fatigue with weakness

dry mouth with thirst

frequent urination with increased volume of urine

numbness of limbs

blurred vision

thirst with preference of drinking water

frequent nocturnal urination

and shortness of breath with inactive talking was in high frequency in those patients who were prescribed Shengmai Yin. The occurrence of fatigue with weakness

thirst with preference of drinking water

blurred vision

frequent nocturnal urination

dry mouth with thirst

numbness of limbs

shortness of breath with inactive talking

and soreness and weakness of lumbus and legs was in high frequency in those patients prescribed Liuwei Dihuang Decoction

and there existed a multi-association among these symptoms. The occurrence of fatigue with weakness

soreness and weakness of lumbus and legs

frequent nocturnal urination

shortness of breath with inactive talking

numbness of limbs

insomnia

and blurred vision was in high frequency in those patients who were prescribed Sijunzi Decoction

and there existed a multi-association among these symptoms.Conclusion The association rule can be adopted to analyze the relationship between formula and syndrome

and to explore the multi-association relationship among the symptoms of type 2 diabetes.