Background: Roundup is one of the economically effective herbicides used in agriculture. It possesses many health hazards to many organs including the adrenal gland. Gallic acid exhibited a high antioxidant potential among phenolic compounds.Aim of the work: To evaluate the histological changes of the suprarenal cortex following exposure to Roundup and the possible ameliorative role of gallic acid in these changes. Material and methods: Twenty-four adult male rats (weighing 250–300 g) were used and equally divided into four groups: Group I (control group) received nothing, Group II (gallic acid-treated group) received 20 mg/kg body weight daily by gastric gavage, Group III (Roundup-treated group) received 0.25 ml/kg body weight daily by gastric gavage and Group IV (Roundup and gallic acid-treated group) received Roundup and gallic acid at the same previous doses. Treatments were administered once daily for 14 days. The adrenal glands were dissected and processed for light and electron microscopic studies. Results: The cells of the suprarenal cortex in the Roundup-treated group were disorganized. Many cells showed darkly stained nuclei and highly vacuolated cytoplasm. The thickness of the adrenal capsule showed a significant increase in addition to significantly increased immunoexpression of caspase-3. Ultrastructurally abundant lipid droplets with degenerated mitochondria within the cells were observed. Coadministration of gallic acid led to the amelioration of these changes. Conclusion: Roundup has destructive structural effects on the adrenal cortex and should be used cautiously. The concomitant gallic acid treatment ameliorated the Roundup-induced alterations.