The present work was planned to determine the median lethal doses (LD₅₀) and to evaluate the haematological and biochemical changes, and histopathological effects of the essential oils from eucalyptus Eucalyptus globules L. and clove Eugenia caryophyllus on liver and kidney of albino rats. The LD₅₀ was 2,334.4 and 3,597.5 mg/kg b.w. of eucalyptus and clove oils, respectively. Obtained data revealed that 1/10 LD₅₀ of both tested oils resulted in a significant increase in WBC counts and produced a significant decrease in haemoglobin concentration and platelets count at 5^th and 10^th doses, as well as RBC counts (-17.1 and -9.4% below normal level) at 10^th dose. The activities of serum GOT and GPT enzymes were a significant increase at 5^th and 10^th doses in treated rats by both tested oils. While two essential oils had mild effect on kidney function, these oils produced a significant increase in creatinine and urea concentration at the 10^th dose. Histopathological studies on liver and kidney revealed that both essential oils caused relatively moderate pathological changes in the liver as congestion of the blood vessels in the portal area associated with inflammatory infiltration. Also, two tested oils induced desquamation of the epithelial cells of the renal tubules.