Ethambutol is an ethylenediamine derivative that is ethane-1,2-diamine in which one hydrogen attached to each of the nitrogens is sutstituted by a 1-hydroxybutan-2-yl group (S,S-configuration). It is a bacteriostatic antimycobacterial drug, effective against Mycobacterium tuberculosis and some other mycobacteria. It is used (as the dihydrochloride salt) in combination with other antituberculous drugs in the treatment of pulmonary and extrapulmonary tuberculosis; resistant strains of M. tuberculosis are readily produced if ethambutol is used alone. It has a role as an antitubercular agent, an environmental contaminant and a xenobiotic. It is a member of ethanolamines and an ethylenediamine derivative.