en تخصصي Special Original articles <strong><em>Introduction:</em></strong> Fluoride (F) and its compounds are widely used in industries in which fluoride overdose leads to various detrimental diseases. In this study the effect of NaOH-modified Eucalyptus leaves on fluoride removal from aqueous solutions as a natural adsorbent was investigated.<br> <strong><em>Materials and Methods:</em></strong> The focus of this study was on the effects of parameters such as pH (2-12), initial concentration (5-30 mg/L), adsorbent dose (0.1-1 g/L) and temperature (25-45 ⁰C). Fluoride residual was measured using the SPADNS method by a DR 5000 spectrophotometer.<br> <strong><em>Results:</em></strong> The maximum adsorption capacity, at pH 2 was found to be 97 mg F/g with an adsorbent dosage of 0.5 g/L and an initial fluoride concentration of 20 mg/L. The adsorption equilibrium and kinetic data were in good agreement with Langmuir Model (R²= 0.967) with qmax = 298 mg/g and pseudo-second order reaction (R² = 0.999).<br> <strong><em>Conclusion:</em></strong> Based on the results, NaOH-modified eucalyptus leaves were found to be able to remove fluoride from aqueous environments with good removal efficiency and adsorption capacity. Eucalyptus, Fluoride Removal, Natural Adsorbent. 481 487 http://jehsd.ssu.ac.ir/browse.php?a_code=A-10-1-75&slc_lang=en&sid=1 Nahid Khoshnamvand Nahidkhoshnam92@gmail.com Yes Nutritional Health Research Center , Lorestan University of Medical Sciences, Khorramabad, Iran. Edris Bazrafshan No Department of Environmental Health, Torbat Heydarieh University of Medical Sciences, Torbat Heydarieh, Iran. Bahram Kamarei No Nutritional Health Research Center , Lorestan University of Medical Sciences, Khorramabad, Iran.