Background: Cerebellar cortexconsists of three layers. The outer molecular, middlePurkinje cell layer, inner granule cell layer. Lithium the alkali metal hasdeleterious effects on nervous tissue and this study proved the injurious effects of lithium on molecular cell layer of cerebellum.

Aim: To observe and report the damaging histological and morphological change of the decrement in the thickness of cerebellar molecular layer by Lithium.

Methods: This study was designed to observe the microscopic changes of thickness of molecular layer in rat cerebellum. For this experimental study 12 animals were used, they were divided into two groups, each comprising of 6 animals.

Results: Group-A received normal lab diet and water ad libitum while group B received injectable lithium carbonate 20 mg/kg/ for 4 weeksrespectively. Micrometry was done and changes of the thickness of molecular cell layer were recorded and documented.

Conclusion: The pernicious effects of Lithium Carbonate on molecular cerebellar cortex were visualized and evaluated .Highly significantly decreased changes of thickness of molecular cell layer were documented in rat cerebellum.

Keywords: Lipidperoxidation,Molecular cell layeratrophy, decomposition