In recent years, the essential oil based drug delivery system has been the focus of interest for solubilizing many aqueous insoluble and highly lipophilic drugs. One such system is the clove oil based microemulsion system that have shown outstanding performance for many such drugs like ramipril, azithromycin, fluconazole, quercetin, bassic acid and diopsyrin. Hence, we intended to assess the toxicity of this system for futuristic in-vivo applications. Histopathological assays and biochemical parameters such as proteins, carbohydrates, free amino acids contents, catalase activity, total reduced glutathione, glutathione-s-transferase, superoxide dimutase were determined in comparison between our microemulsion system treated and control animals. Significant changes were observed between the treated and control and their LC 50 value was determined at a volume of 200μl dispersed in a measured quantity of water. The safety limit of the drug delivery vehicle is observed, however, when the dosage limit exceeds it is not considered safe enough. Extensive studies are being carried out on rats to determine the dosage limit. Copyright © 2014 American Scientific Publishers All rights reserved.