Isoniazid (INH) is a potent bactericidal antibiotic used in the treatment of tuberculosis. Treatment with INH therapy has a risk of toxicity, which can be acute or chronic. Acute toxicity manifests as neurological symptoms. Consumption of 2 g of INH can predispose a patient to acute toxicity; while chronic toxicity usually presents as hepatotoxicity and peripheral neuropathy.  There are 2 known syndromes of hepatotoxicity:  1. Mild type manifesting as transient and asymptomatic elevation in serum aminotransferase levels. 2. Severe acute hepatitis which can sometimes be fatal[1]. Peripheral neuropathy is secondary to a deficiency of vitamin B6 (pyridoxine).