Introduction: Tramadol uptake is associated with many side effects. Thyme has been presumed to have a neuroprotective effect against brain damage. Aim of the work: TO assess the harmful effects of tramadol on the pre and postnatal development of the cerebellar granule cells and to evaluate the possible ameliorative effect of thyme if being administered with tramadol simultaneously. Material & Methods: Three sets of forty-eight mature female albino rats were randomly organized into three equal groups; control (G1), tramadol treated (G2) and tramadol+thyme treated (G3). After pregnancy, the pregnant rats of each group were categorized into a group designed to be sacrificed at the gestational ages 13th, 16th and 19th for the prenatal study. In the other pregnant rat group, their offspring were further subdivided according to their ages into 3 subgroups (newborn, 10th and 20th postnatal day) for postnatal evaluation. G1 was not given any treatment. Tramadol HCL (40 mg/Kg/day) dissolved in tab water was given orally to G2. Tramadol (40 mg/Kg/day) and thyme extract (500 mg/kg/day) were given orally to G3. A light, electron microscopic examination and morphometric analysis were performed in the study. Results: By light and electron microscopic examination, there were degenerative and apoptotic changes in the cerebellar cortex of G2. G3 showed improvement in histological changes. Morphometric results showed a decrease in the cerebellar cortex thickness between the G1 and G2 which was significant and an increase in the cerebellar cortex thickness G3 when compared with that of G2.