Pharmacognostical studies were carried out on the stem bark of Thevetia neriifolia Juss. which showed rhytidoma with suberized cork, cortex, starch grains, prism of calcium oxalate crystals, lignified stone cells, secondary phloem with medullary rays. Physicochemical parameters such as water and alcohol soluble extractive values were found to be 20 % and 21.6 % w/w for the stem bark. The total ash value, acid insoluble ash and water soluble ash were found to be 7 %, 1.6 % and 2.5 % w/w respectively. The loss on drying (12 % w/w) was also determined.