Activity of Ethanol Extract of Songga Wood (Strychnos lucida) as an Antimicrobial and Antibiofilm Agent Against Bacillus species, Salmonella typhi and Candida albicans.

&lt;b&gt;Background and Objective:&lt;/b&gt; The extensive use of antibiotics has created selective pressure leading to antimicrobial resistance, with biofilm formation serving as a major defense mechanism. Nearly 80% of infections involve biofilm-producing microorganisms that conventional antibiotics fail to eradicate. This study aimed to evaluate the antimicrobial and antibiofilm properties of ethanol extract from songga wood (&lt;i&gt;Strychnos lucida&lt;/i&gt;) against &lt;i&gt;Bacillus&lt;/i&gt; sp., &lt;i&gt;Salmonella typhi&lt;/i&gt; and &lt;i&gt;Candida albicans&lt;/i&gt;. &lt;b&gt;Materials and Methods:&lt;/b&gt; Antimicrobial and antibiofilm activities of &lt;i&gt;S. lucida&lt;/i&gt; ethanol extract were assessed using the microdilution assay at graded concentrations (0.0625-1%). Biofilm inhibition was examined during both intermediate and maturation phases. Statistical analysis was performed to determine significance (p<0.05). &lt;b&gt;Results:&lt;/b&gt; At the highest tested concentration (1%), the extract demonstrated strong antimicrobial activity, inhibiting 83.89% of &lt;i&gt;Bacillus&lt;/i&gt; sp., 80.03% of &lt;i&gt;S. typhi&lt;/i&gt; and 82.43% of &lt;i&gt;C. albicans&lt;/i&gt;. Pronounced antibiofilm activity was also observed, with inhibition rates of 75.36, 75.58 and 71.82% during the intermediate phase and 61.16, 61.76 and 61.14% during the maturation phase, respectively (p<0.05). &lt;b&gt;Conclusion:&lt;/b&gt; &lt;i&gt;Strychnos lucida&lt;/i&gt; ethanol extract exhibited significant antimicrobial and antibiofilm effects, indicating its potential as a natural candidate for developing alternative therapeutic agents. Further studies on its active compounds and mechanisms are warranted to support clinical applications.