Enrofloxacin, also known as ethyl ciprofloxacin . It is a slightly yellow or light yellow crystalline powder, with a bitter taste and insoluble in water. This product is designated as an animal specific medicine by the country. Enrofloxacin is a chemically synthesized antibacterial agent belonging to the fluoroquinolones class, which is easily soluble in organic solvents such as sodium hydroxide solution, methanol, and cyanomethane. This product is a broad-spectrum fungicide with special effects on Mycoplasma. It has bactericidal effects on Escherichia coli, Klebsiella pneumoniae, Salmonella, Proteus, Pseudomonas aeruginosa, Hemophilus, Pasteurella multocida, Pasteurella hemolysis, Staphylococcus aureus, Streptococcus, etc. Enrofloxacin can be used as an animal drug with a long half-life and good tissue distribution in animals. It is a broad-spectrum antibacterial agent and has antibacterial effects on Gram positive bacteria, negative bacteria, and mold forms. It has been used in the control of Vibrio and Escherichia coli diseases in aquaculture fish. This product is a synthetic third-generation quinolone antibacterial drug, also known as ethyl ciprofloxacin. It was approved by the FDA on October 4, 1996 and is a specialized quinolone antibacterial drug for livestock, poultry, and aquatic products. It can bind to bacterial DNA gyrase subunit A, thereby inhibiting the enzyme's cutting and connecting functions, preventing bacterial DNA replication, and exhibiting antibacterial effects. It has broad-spectrum antibacterial activity and strong permeability. This product has a strong killing effect on Gram negative bacteria and also has good antibacterial effects on Gram positive bacteria. It is well absorbed orally, has a high and stable blood concentration, and can be widely distributed in tissues. Its metabolic product is ciprofloxacin, which still has strong antibacterial effects. Almost all pathogenic bacteria in aquatic animals have strong antibacterial activity. It is effective against severe infections caused by drug-resistant pathogens and has no cross resistance with other antibiotics.