en Anti-microbial agents, resistance and treatment protocols Anti-microbial agents, resistance and treatment protocols Original article Original article <strong>Introduction: </strong><em>Candida albicans </em>can cause various diseases, which might lead to various cases of life-threatening diseases. Biofilm is a specific feature of <em>C. albicans</em> formed on mucosal surfaces and medical devices. Moreover, biofilm protects <em>Candida</em> cells from antifungals and makes the treatment challenging. Here, we studied the effects of dehydrozingerone on <em>C. albicans</em> growth, ergosterol biosynthesis, biofilm formation, and the expression of an essential gene involved in yeast-hypha transition. <strong>Methods:</strong><em> C. albicans</em> cells were treated with serial two-fold concentrations of dehydrozingerone (0.125-2 mg/ml) for 48 h at 35 &deg;C. The weights of the fungal cells were estimated as a sign of fungal growth. Biofilm formation was evaluated by a tetrazolium salt (XTT) reduction assay. The expression of the <em>HWP1</em> gene was assayed by real-time PCR. <strong>Results: </strong>Dehydrozingerone inhibited <em>C. albicans</em> growth in the range of 3.57% to 84.28%, dose-dependently. The ergosterol content of yeast cells was reduced by 50% in the highest concentration. The biofilm formation was also inhibited by more than 50% at the highest concentration. The expression of the <em>HWP1</em> gene was suppressed by dehydrozingerone at different concentrations. <strong>Conclusion:</strong> Our results indicate that dehydrozingerone displayed effective activity against growth, biofilm formation, and ergosterol biosynthesis in <em>C. albicans in vitro</em>. Dehydrozingerone, Candida albicans, Ergosterol, Biofilm, HWP1 gene 76 81 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-131-2&slc_lang=en&sid=1 Zahra Jahanshiri zjahanshiri@yahoo.com 0000-0001-9431-9335 Yes Department of Mycology, Pasteur Institute of Iran, Tehran 1316943551, Iran Sepideh Nejatbakhsh 0000-0002-0517-235X No Department of Mycology, Pasteur Institute of Iran, Tehran 1316943551, Iran