Stress is considered a normal part of people's lives. But constantly living in a state of high stress causes the body to become exhausted. Unfortunately, adolescents are the most vulnerable and stress, if handled carelessly, can lead to serious health problems, both mentally and physically (Christopher, 2015). Therefore, researchers have developed drugs to treat stress, such as commercial stress relievers, which are undeniably expensive. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay So, after learning from a research study that fish bile contains pharmaceutical residues such as sertraline, the researchers were motivated to conduct a study titled “Milkfish Bile Extract (Chanos Chanos) and its ability to reduce stress levels: an in vivo study on white mice (Mus Musculus).” This study aimed to determine the effectiveness of milkfish bile in terms of reducing stress levels. Specifically, this study sought to answer the following questions: Is milkfish bile extract effective in reducing stress levels in terms of decreasing the immobility time of mice? Is there a significant difference between the effectiveness of commercially available stress reliever and milkfish bile extract in terms of reducing stress levels? In the data collection procedures, the white mice subjected to the study underwent acclimation. Next, the collected milkfish bile was extracted. Mice from all setups were subjected to the pre-forced swimming test for five minutes. After the pre-FST, they were subjected to the pre-tail suspension test for 3 minutes. The interventions were then administered orally in Set-up A with diluted Milkfish Bile Exract and in Set-up B with a commercial stress reliever (Mirtazapine). Twenty-four hours after administration of the interventions, mice were prepared for post-FST and post-TST. Both Set-up A (Milkfish Bile) and Set-up B (Mirtazapine) results showed a decrease in immobility time of mice after post-FST and post-TST. Nonetheless, the results of Set-up C showed that failure to intervene could not decrease but could amplify stress levels, which is why an increase in immobility time was observed. The ANOVA revealed that the f value is less than the critical f value. Therefore, it was concluded that milkfish bile extract was proven effective in reducing stress levels. However, there is no significant difference between the efficacy of milkfish bile extract and mirtazapine in terms of reducing stress levels during the post-FST and post-TST periods..