Spectinomycin dihydrochloride is primarily used as an antibiotic in veterinary and human medicine. In veterinary applications, it is effective in treating bacterial infections in livestock, particularly respiratory and gastrointestinal infections in cattle, swine, and poultry. It is also used to control outbreaks of diseases such as salmonellosis and colibacillosis in animals. In human medicine, it is employed to treat gonorrhea, especially in cases where penicillin resistance is observed. Its mechanism of action involves inhibiting bacterial protein synthesis, making it a valuable tool in combating bacterial infections. Additionally, it is sometimes used in research settings as a selective agent in molecular biology experiments to study bacterial resistance mechanisms.