Used as an antibiotic to treat bacterial infections, particularly tuberculosis caused by Mycobacterium tuberculosis. Effective against a wide range of gram-negative bacteria (e.g., Yersinia pestis for plague, Brucella spp.) and some gram-positive bacteria. Commonly applied in medical treatment, often in combination with other antimicrobials when first-line drugs are not suitable, to prevent resistance. Also utilized in veterinary medicine to control infections in livestock. In agriculture, it helps manage bacterial diseases in crops, especially in fruit trees and vegetables, though its use is restricted in many countries due to residue concerns and health impacts. In biological research, it serves as a selective agent in cell culture media or microbial cultures, particularly for selecting plant cells or genetically modified bacteria with antibiotic resistance genes, and to prevent bacterial contamination, such as in mouse embryonic cell culture. Its use is limited due to potential toxicity and the development of bacterial resistance.