Objective: To investigate the medication rules of traditional Chinese Medicine (TCM) for treating impotence. Method: The prescriptions for treating impotence that from TCM classics and famous TCM doctors were collected to build a database based on TCM inheritance assist system. Association rules algorithm and entropy clustering methods were used to mine the frequency of single drug and drug combinations

the association rules between drugs

and so on. Result: Based on the analysis of prescriptions for treating diabetes

the highest frequency of single drugs were Cuscutae Semen

Rehmanniae Radix Praeparata

Angelicae Sinensis Radix

Lycii Fructus

and Epimedii Folium. The most frequency drug combinations were 'Lycii Fructus

Cuscutae Semen'

'Cistanchis Herba

Cuscutae Semen'

'Lycii Fructus

Epimedii Folium'and so on. When confidence was over 0.85

the drug combinations of association rules were 'Poria->Cuscuta Semen'

'Rehmanniae Radix Praeparata->Lycii Fructus'

'Bupleuri Radix->Angelicae Sinensis Radix'

and so on. Conclusion: In TCM

the drugs used for treating impotence were often with the actions of warming and invigorating kidney Yang

and nourishing Qi and blood.