Eucalyptus oil is used in a wide range of medicinal and other uses, and the current study aims to estimate the median lethal dose LD50 of eucalyptus oil of Eucalyptus camaldulensis and estimate the pathological effect of eucalyptus oil in mice. Eucalyptus oil was obtained in the study by extracting the leaves of the plant Eucalyptus camaldulensis using hydrodistillation. Toxicity testing was performed by dividing mice into groups that you treated with different doses of eucalyptus oil 1200, 1600, 2000, and 2400 mg/kg. The current study showed that the average lethal dose, the LD50, was 1820 mg/kg. The study suggested the emergence of clinical signs in mice when consuming eucalyptus oil in high doses, such as slow movement, suffocation, and convulsion, compared with the control group and the group that administered a lower dose, It was observed that high doses of eucalyptus oil could cause damage to the lung, liver, kidneys, and heart, as the lung was the organ most affected by the oil, followed by the liver, kidneys, and then the heart, and it was less affected by eucalyptus oil, and this indicates that eucalyptus oil, when administered orally in high doses, causes clear toxicity effects. Eucalyptus oil is a safe medicine for external use. Keywords. Eucalyptus oil, LD50; Administrated; Lung; Liver; Heart; Kidney; Mice.