As important traditional Chinese medicine materials, medicinal animals have been highly appreciated due to their strong bioactivities. Among these, medicinal insects have been thought to be significant, especially in preventing and treating modern diseases and tumors. Some of the most famous medicinal insects, such as horseflies, blister beetles and American cockroachs ( Periplaneta americana
) have been well known due to their reported effects in anti-thrombosis and fighting cancer. In general, identifying the medicinal functions and active components of medicinal insects has been a gradual processes. Originally, these medicinal insects were collected from open fields and usually their whole bodies were adopted. But, currently, most medicinal insects are under large-scale artificial propagations and only their purified active components are in use. In this article, we reviewed the historical process of the application of the horsefly in traditional Chinese medicine and tried to provide useful references for the modernization of traditional Chinese medicines via discussing the interrelationship between traditional Chinese medicine and western medicine.