The aim of the present investigation is to evaluate the protective effect of mitochondria–targeted gallic acid against Pseudomonas aeruginosa induced thyroid gland toxicity in female Swiss albino mice. Female Swiss albino mice weighing 28–32gm randomly divided into three groups and each group consist of five animals. The first group considers as control treated with only DMSO, the second group is DMSO + Pseudomonas aeruginosa treated and the third group is DMSO + Pseudomonas aeruginosa + mt–G treated, a whole experiment performed for fourteen days. The presence of the microflora population in the gut in balanced form showed the normal function of the thyroid gland whereas the gut microflora population are imbalanced affects thyroid function. Pseudomonas aeruginosa cause increased body weight, level of T3, T4, decreased, level of TSH did not show significantly changes and increased the activity of catalase, SOD,LPO, LDH, MDH and decreased the activity of GPx were determined. The mt–G is influential sufficient to ameliorate the thyroid toxicity caused by bacteria Pseudomonas aeruginosa.