Objective:To monitor the pathological alterations in pancreas of rat during experimental fluorosis. Methods:Sixty Sprague Dawley albino rats of both sexes were divided into 12 experimental groups and one control group.The rats of control group were administered subcutaneously double distilled water 1 mL/kg bw daily.The experimental groups were injected with 30,45,and 75 mg NaF/kg bw/day.The experimental period was divided into 4 phases at interval of 15,22,30,and 36 days.Animals were sacrificed from each group at the end of 16,23,31,and 37 days.Results: The following changes were observed in this study:(1) Pathological examination of pancreas after 15 days of fluoride treatment revealed:hypertrophy of acini,leucocytes infilteration and pycnouc nuclei due to necrosis of acini in group 1;uremic alterations,invulsion and infoldings of reticular layer of islets of Langerhans in group 2;and a decrease in number of acini and interlobular connective tissues resulted in an increase in intercellular spaces in pancreas of rats in group 3.(2)Hyalinization and hypertrophy in the lobules of acini and hyperplasia and hypertrophy in intercalated duct with mucinous secretion in pancreas of rat of group 4;squamous metaplasia of pancreatic duct,adenoma of pancreas,hemorrhagic necrosis in group 5;and hyperplasia of acini and reduction in number of pancreatic islets in group 6.(3) Disorganization and atrophy of pancreatic lobules and presence of vacuoles in a group of six were visible in pancreas of rats in group 7;acute pancreatic and lamellated inflammatory cells in test rats of group 8;and islet adenoma and decrease in number of islets cells,and exudation in acini were noticed in experimental rats of group 9.(4) In the last phase of experimentation,atrophic alterations in pancreatic acini,invulsions,and necrosis was prominent in group 10,deep inflammation and proliferation of connective tissue of pancreas in experimental group 11,and periodical fibrosis, hyperplasia of acini,degenerative changes in pancreas of rats in group 12.Conclusion:The histopathological examination of pancreas of fluoridated rats exhibited structural alterations in the exocrine glands.The acini revealed hypertrophy,pyknotic nucleus,necrosis and uremic alterations.Acini became lobulated and reveal increased pigmentation. Methods: Sixty Sprague Dawley albino rats of both sexes were divided into 12 experimental groups and one control group. The rats of control group were administered subcutaneously double distilled water 1 mL / kg bw daily.The experimental groups were injected with 30,45, and 75 mg NaF / kg bw / day. The experimental period was divided into 4 phases at intervals of 15, 22, 30, and 36 days. Animals were sacrificed from each group at the end of 16, 23, 31, and 37 days. Results: The following changes were observed in this study: (1) Pathological examination of pancreas after 15 days of fluoride treatment revealed: hypertrophy of acini, leucocytes infilration and pycnouc nuclei due to necrosis of acini in group 1; uremic alterations, invulsion and infoldings of reticular layer of islets of Langerhans in group 2; and a decrease in number of acini and interlobular connective tissues resulted in an increase in intercel Lular spaces in pancreas of rats in group 3. (2) Hyalinization and hypertrophy in the lobules of acini and hyperplasia and hypertrophy in intercalated duct with mucinous secretion in pancreas of rat of group 4; squamous metaplasia of pancreatic duct, adenoma of pancreas, hemorrhagic necrosis in group 5; and hyperplasia of acini and reduction in number of pancreatic islets in group 6. (3) Disorganization and atrophy of pancreatic lobules and presence of vacuoles in a group of six were visible in pancreas of rats in group 7; acute pancreatic and lamellated inflammatory cells in test rats of group 8; and islet adenoma and decrease in number of islets cells, and exudation in acini were noticed in experimental rats of group 9. (4) In the last phase of experimentation, atrophic alterations in pancreatic acini , invulsions, and necrosis was prominent in group 10, deep inflammation and proliferation of connective tissue of pancreas in experimental group 11, and periodical fibrosis, hyperplasia of acini, degenerative changes in pancreas of rats in group 12. Conlusion: The histopathological examination of pancreas of fluoridated rats showed structural alterations in the exocrine glands.The acini revealed hypertrophy, pyknotic nucleus, necrosis and uremic alterations. Aci became lobulated and reveal increased pigmentation.