Abstract: The present study aimed to investigate the effect of grazing intensity on dynamics of Alkanna populations that grow in Saint Catherine mountains. Seventy plots (4x4 m2) were selected to represent variation of Alkanna orientalis population under different degrees of grazing and human disturbances. The results showed that four main groups of Alkanna population can be recognized. These groups differ significantly in the percentage of coverage, average of flower buds, flowers, fruits, plant height and grazing intensity and soil organic content. Insignificant variation in the soil moisture content, natality, and mortality were indicated. The impact of grazing and fencing was seen through the comparison between fenced and unfenced populations. The results revealed that the vegetation cover, average of plant height and reproductive organs (floral buds) increased for unfenced population as compared to fenced while percentage of dryness and average number of fruits was higher in fenced population. The results of natality and mortality showed that the four groups of Alkanna populations have different rates of natality occurring at third and fourth groups of populations (heavily grazed), whereas the mortality rate of first group was very high as compared to a very low rate in the fourth group.