Introduction: Intracanal medicament has been widely advocated to help eliminate pulpal or periapical tissue microorganism either as local dressing after excavation of carious lesions or as a root canal medicament. Herbal medicine, also called “botanical medicine” or “phytomedicine”, refers to the use of plant seeds, berries, roots, leaves, bark, or flowers for medicinal purposes. Ocimum sanctum (Holy basil, Tulsi) is a plant native to India and has been known to have antimicrobial and anti inflammatory properties. The present pilot clinical study used Ocimum sanctum’s essential oil extract to test its anti inflammatory properties in deep carious teeth with irreversible pulpitis slated for extraction. Materials and methods: Six patients with irreversibly inflamed pulp in carious third molar slated for extraction were randomly divided into two groups. Gross carious excavation was done in all the selected teeth. IRM restoration was placed in teeth of control Group A while cotton pellet dipped in Ocimum sanctum’s essential oil extract was placed in group B before restoration. Both groups were called after 48 hrs for extraction and teeth were longitudinally grooved with a fissure bur and split in half. The dental pulps were extracted carefully from all the teeth using a spoon excavator which was fixed in 10% formalin solution. It was then subjected to dehydration with graded alcohol 70%, 80%, and 90% successively. The tissue embedding was done in blocks of paraffin wax after clearing with Xylene. The specimens were examined under compound microscope after staining with haemotoxylin and eosin stain. Results: Group A (Control): Cellular collagenous pulp tissue showing interstitial edema with moderate diffuse infiltrate of neutrophilic polymorphonuclear cells with evidence of acute inflammation. Group B (Ocimum Sanctum (Tulsi) essential oil extract): Cellular collagenous pulp tissue with no evidence of acute inflammation was seen. Conclusion: After 48 hours deep carious third molars in contact with Tulsi oil the mediators of acute inflammation was totally eliminated. Thus extract showed its efficacy against acute inflammation.