An antibacterial substance obtained from the soil mould, Streptomyces griseus, isolated in 1944 and the first antibiotic to be effective against the tubercle bacillus. It was once routinely used to treat TUBERCULOSIS; because of side-effects and the development of other drugs, it is now rarely used except in cases of resistant disease.

Its main disadvantage is its toxic effects, especially disturbance of the vestibular and hearing apparatus. This may result in DEAFNESS, VERTIGO, and TINNITUS which may be permanent.