This is a placebo-controlled, 12 weeks, with a sample of 130 bipolar patients who sought treatment at the outpatient clinic of the Hospital of clinical psychiatry at State University of Londrina clinical trial , double-blind , randomized, from May 2015 to May 2016. Patients will be randomly allocated into two groups, double-blind, to receive a combination product (NAC, 1.8 g/day) or placebo for a period of 12 weeks. Both groups remain receiving maintenance treatment in outpatient psychiatry , and general medical and routinely reviews psychiatric . The dosage will be fixed 1.8 g /day of NAC administered in capsules taken 1 before breakfast, 1 before lunch and 1 before dinner is equal doses.