Ethambutol is an antibacterial agent that stops the growth of TB cells resulting in its death.

Isoniazid is an antibiotic that is used to kill the bacteria that cause tuberculosis (TB). Its exact mechanism of action is unknown but it is thought to prevent the bacteria from making components called mycolic acids which are needed to form cell walls. It combines with an enzyme which interferes with the cell metabolism of the bacteria. As a result of the disruption of its metabolism and without a cell wall the bacteria die.

Rifampicin is an antibiotic that is used to treat tuberculosis. It inactivates a bacterial chemical called RNA-polymerase. These TB bacteria use RNA-polymerase to create proteins and make their own genetic information. The TB bacteria cannot survive without this chemical.