A capsule-based formulation containing artificial bezoar, Strychni pulveratum (strychnos powder), camphol alcohol (borneol or borneo camphor) and extracts from Zedoary rhizome (Rhizoma curcumae), Pseudobulbus cremastrae seu pleiones (dried pseudobulb of Cremastra appendiculata), Yatantzu (seed of Brucca javanica), beehive, Bombyx mori (Bombyx batryticatus or silkworm), Danshen (dried root of Salvia miltiorrhiza or red sage root), Radix astragali, and Angelica, with potential antineoplastic activity. Upon oral administration of the cidan herbal capsule, the active ingredients in the plant extracts may induce tumor cell apoptosis and reduce tumor cell proliferation.