Konsumsi parasetamol dosis toksik dapat mengakibatkan stres oksidatif hepar. Efek stres oksidatif ini dapat dikurangi dengan pemberian antioksidan dari bawang putih (Alliumsativum). Penelitian ini bertujuan untuk mengetahui pengaruh pemberian ekstrak bawang putih terhadap struktur histologis hepar mencit (Mus musculus) dan peningkatan dosis dapat meningkatkan efek perlindungan terhadap struktur histologis hepar mencit yang diinduksi parasetamol dosis toksik. Metode. Penelitian ini merupakan penelitian laboratorium eksperimental. Hewan uji yang digunakan adalah mencit jantan galur Swiss webster berusia 2-3 bulan, berat ±20 gram. Sampel 30 mencit diambil secara incidental sampling. Sampel dibagi secara random menjadi 5 kelompok, setiap kelompok terdiri 6 mencit. Kelompok Kontrol Normal (KKN) mendapatkan akuades. Kelompok Kontrol Induksi (KKI) mendapatkan perlakuan akuades dan parasetamol (5mg/hari) pada tujuh hari terakhir. Kelompok Perlakuan 1 (KP1), Kelompok Perlakuan 2 (KP2), dan Kelompok Perlakuan 3 (KP3) secara berturut-turut diberi ekstrak bawang putih (Allium sativum) dengan dosis 2 mg/hari, 5 mg/hari, dan 10mg/hari selama 30 hari, kemudian juga diberikan parasetamol (5 mg/ hari) pada tujuh hari terakhir. Pada hari ke 31 mencit dikorbankan dan hepar diambil dan dibuat preparat dengan pengecatan HE. Preparat histologi hepar dinilai berdasarkan jumlah hepatosit yang intinya mengalami piknosis, karioreksis, dan kariolisis. Data yang didapatkan dianalisis menggunakan uji One-Way ANOVA dan dilanjutkan uji Post hoc Multiple Comparison (α=0,05). Hasil Penelitian. Rerata hepatosit yang rusak pada kelompok KKN 8,75±3,957; KKI 49,00±6,701; KP1 41,33±5.449; KP2 20,53±3,964; dan KP3 21,58±4,750. Dari uji One-Way ANOVA didapatkan nilai p sebesar 0,000 (p<0,05). Hasil uji Post hoc multiple comparisons menunjukkan perbedaan bermakna antara KKN-KKI, KKN-KP1, KKN-KKP2, KKN-KP3, KKI-KP1, KKI-KP2, KKI-KP3, KP1-KP2, KP1-KP3, tetapi antara KP2-KP3 terdapat perbedaan yang tidak bermakna. Simpulan Penelitian. Ekstrak bawang putih dapat melindungi struktur histologis hepar mencit yang diinduksi parasetamol dosis toksik. Peningkatan dosis ekstrak bawang putih dari dosis 2mg/hari hingga dosis 5mg/hari dapat meningkatkan efek perlindungan struktur histologis hepar mencit yang diinduksi parasetamol dosis toksik. Kata Kunci: Bawang putih (Allium sativum), paracetamol, hepar, mencit ABSTRACT Background.Consuming paracetamol in toxic dose can cause oxidative stress to the liver. This oxidative stress effect can be decreased by giving antioxidant agent contained in garlic . This study aims to know protective effect of garlic (Allium sativum) extract on liver histological structure of mice (Mus musculus) induced by toxic dose of paracetamol and to know the effect of increasing dose of the extract on its protective effect. Methods. This study was experimental laboratoric research. The samples were Swiss webster mice, 2-3 month old, and ±20 grams weight. The samples were randomly divided into 5 groups, which each group consisted of 6 mice. Mice in Normal Control Group (KKN) got distilled water, Induced Control Group (KKI) got distilled water and toxic dose of paracetamol (5mg per day) for last 7 days. Mice in Treated Group 1 (KP1), Treated Group 2 (KP2), Treated Group 3 (KP3), consecutively got 2mg, 5mg, and 20mg per day of garlic extract for 30 days and the last 7 days they got toxic dose of paracetamol (5mg per day). In 31st day mice were sacrificed and the liver were taken and stained with HE for histological preparation. Histological preparation were evaluated by counting hepatocytes which had pyknosis, karyorrhexis, and karyolysis. The data were analyzed using One-Way ANOVA and using Post hoc Multiple Comparisons (α=0.05). Results. Mean of damaged hepatocytes in the group of KKN, KKI, KP1, KP2, and KP3 were 8.75±3.957; 49.00±6.701; 41.33±5.449; 20.53±3.964; and 21.58±4.750. The One-Way ANOVA test showed that p value was 0.000 (p<0.05). The Post hoc Multiple Comparisons showed that there were significant differences between KKN-KKI, KKN-KP1, KKN-KKP2, KKN-KP3, KKI-KP1, KKI-KP2, KKI-KP3, KP1-KP2, KP1-KP3. But the difference between KKP2-KKP3 was not significant. Conclusion.Garlic (Allium sativum) extract was able to protect liver histological structure of mice induced by toxic dose of paracetamol. Increasing dose of Garlic (Allium sativum) extract from 2mg to 5mg per day was able to increase the protective effect of liver histological structure of mice induced by toxic dose of paracetamol. Keyword: Garlic (Allium sativum), Paracetamol, Liver, Mic