en عمومى General مقاله اصیل Original Article <div style="text-align: justify;">Background: The presence of medicines in the environment is considered as a serious threat to the human health. The entrance of these substances into the water sources causes soil pollution, which eventually leads to the environmental pollution and it creates some problems for the public health. Also, increasing antibiotic resistant bacteria has attracted the attention of researchers to the use of natural resources such as marine products, for producing new antibiotics. The aim of this study was to evaluate antimicrobial activities of powdered cuttlebone against Klebsiella oxytoca, Staphylococcus aureus, and Aspergillus flavus.<br> Methods: At first, cuttlebones were washed, dried, and powdered. Then, the powdered cuttlebone was characterized. In the next step, its antimicrobial activities were evaluated using agar well diffusion technique, and minimum inhibitory concentration (MIC) was calculated.<br> Results: The powdered cuttlebone was found to be effective against K. oxytoca (24 mm, MIC: 10-1 mg/mL), but no antimicrobial response was found against S. aureus. Also, the powdered cuttlebone antifungal activity and MIC against A. flavus were recorded 23 mm and 10-1 mg/mL, respectively.<br> Conclusion: The obtained results suggest antimicrobial activities of powdered cuttlebone, which are concentration dependent. Furthermore, cuttlebone can be used as an accessible natural source to provide novel, low cost, and safe antimicrobial agents.</div> Antibacterial activity, Antibiotics, Antifungal activity, Marine products, Minimum inhibitory concentration 39 45 http://ehemj.com/browse.php?a_code=A-10-1-200&slc_lang=en&sid=1 Ghazal Yazdanpanah ghazal.yazdanpanad@gmail.com 10031947532846007762 10031947532846007762 No Environmental Health Engineering Research Center, Kerman University of Medical Sciences, Kerman, Iran Neda Javid n.javid1367@gmail.com 10031947532846007763 10031947532846007763 No Environmental Health Engineering Research Center, Kerman University of Medical Sciences, Kerman, Iran Zhila Honarmandrad zhila.honarmandrad@pg.edu.pl 10031947532846007764 10031947532846007764 No Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdansk University of Technology, 80-233 Gdańsk, 11/12 Narutowicza Str, Poland Najmeh Amirmahani mahan16095@yahoo.com 10031947532846007765 10031947532846007765 No Environmental Health Engineering Research Center, Kerman University of Medical Sciences, Kerman, Iran Alireza Nasiri nasiri_a62@yahoo.com 10031947532846007766 10031947532846007766 Yes Corresponding author: Environmental Health Engineering Research Center, Kerman University of Medical Sciences, Kerman, Iran