The invention relates to a 
drug for controlling a fish gas 
disease which is characterized by being prepared from the following raw materials in parts by weight: 30-40 parts of 
gall nut, 30-40 parts of Chinese teasel root and 20-40 parts of salt. A preparation method comprises the steps of: weighting 30-40 parts of 
gall nut and 30-40 parts of Chinese teasel root in parts by weight; adding water in the proportion of 1:10-12 relative to the total weight of the raw materials, soaking for 20-30min, decocting twice according to a conventional method; decocting with 
slow fire for 30-40min after first boiling, filtering; adding 6-8 times of water in filter residue for boiling and then decocting with 
slow fire for 20-30min, filtering; merging two times of filtrate, then filtering, condensing the filtrate at a temperature of 40-50 DEG C until the 
relative density is 1.05-1.20; finally, cooling concentrate to 
room temperature; then weight 20-40 parts of salt, slowly adding into concentrate for dissolving the salt, and packaging into 5000ml / 
bottle. The invention has the advantages of reasonable formula, simple preparation and environment protection without 
pollution, effectively controls the fish gas 
disease through synergistic effect of the raw materials, promotes the 
fish growth, improves the 
survival rate, and remarkably enhances the economic benefit.