The invention provides a composite 
plant extract 
feed additive for preventing 
swine dysentery. The composite 
plant extract 
feed additive is mainly prepared from the following components of 5-10 parts of 
Chinese gall tannic acid, 20-50 parts of a 
plant essential oil composite, 3-6 parts of garlicin, 3-6 parts of 
lauric acid and esters thereof, 3-6 parts of acanthopanax 
polysaccharide, 3-6 parts of a solubilizer and 42-50 parts of carriers, wherein the plant 
essential oil composite is mixed and compounded from 3-6 parts of 
rosemary oil, 5-10 parts of 
thyme oil, 3-6 parts of folium eucalypti oil and 10-25 parts of cretian 
origanum oil. The addition proportion of the composite plant extract accounts for 0.01%-0.3% of a pig feed. The composite plant extract 
feed additive is prepared from natural plant extracts, can effectively prevent 
swine dysentery, and protect large intestines and caecums from being damaged by serpulina hyodysenteriae. In addition, through the composite plant extract feed additive disclosed by the invention, the 
immunity of animals can also be adjusted, the occurrence rate of diarrhoea and respiratory diseases can be reduced, and the growing performance of the animals is improved. The composite plant extract feed additive can be applied to pigs at various growth phases, is free from residues of 
veterinary drugs, does not have 
withdrawal time, does not generate 
drug tolerance, and is a novel green feed additive for preventing the 
swine dysentery.