Backgrounds: Etomidate is one of anesthetic agent which has minimal effect on cardiovascular function. However, etomidate depress cortisol production. Vitamin C is one of the agent that hamper the effect of etomidate toward cortisol production. Objectives: To analyze the effect of pre-treatment with vitamin C 200 mg on cortisol serum concentration in elective surgery under general anesthesia. Method: This double blind, Randomized Controlled Trial with 30 subjects which divided into two groups (n=15), control group and treatment group which received etomidate 0,2 mg/kgBW and combination of etomidate and vitamin C 200 mg in pre-operation respectively. Each group was then examined for cortisol serum concentration pre-anesthesia, 2 hours post induction, and 8 hours post induction. Wilcoxon Signed Rank Test and Paired T Test was performed to compare cortisol serum concentration in each group. While Mann Whitney and Independent Sample T Test was used to compare between control and treatment group. Results: Cortisol serum concentration in control group between pre-anesthesia ;244,15 (181,39-382,75)] and 2 hours post induction [185,52 ± 35,88]; and between 2 hours and 8 hours post induction [349,81 ± 121,28] was significantly different with value 0,002 and 0,000 respectively. It showed that decrement of etomidate dosage mo 0,2 mg/kgBW still able to decrease cortisol serum production significantly. However, in treatment group cortisol serum concentration pre-anesthesia [258,49 1"5,45-369,09)] and 2 hours post induction [202,14 ± 45,3]; and between 2 hours and 8 hours post induction [251,39 ± 122,91] was non significant, with p value 0,256 and 0,691 respectively. It proved the negative effect of vitamin C on cortisol depression effect of etomidate. Cortisol serum concentration between control and treatment group was significantly different on 2 hours post induction, but non significant on 8 hours post induction. It showed that the negative effect of vitamin C in cortisol depression because of etomidate only significant during 8 hours post eduction Conclusions: The effect of Vitamin C 200 mg iv 30 minutes pre-operation can minimize Cortisol depression on administration of etomidate 0,2 mg/kgBW Keywords : Pretreatment, vit c 200 mg, cortisol serum, etomidate ABSTRAK Latar Belakang: Etomidat adalah salah satu agen anestesi yang berefek minimal terhadap kardiovaskular. Namun, etomidat mendepresi produksi kortisol. Salah satu agen yang dapat meminimalisir efek depresi tersebut adalah vitamin C. Tujuan: Tujuan penelitian ini adalah menganalisis pengaruh pretreatment vitamin C 200 mg pada operasi elektif dengan anestesi umum terhadap kadar kortisol serum. Metode: penelitian ini merupakan penelitian Randomized Contolled Trial dengan 30 subjek yang dibagi dalam dua kelompok sama besar (n=15), yaitu kelompok kontrol yang menerima etomidat 0,2 mg/kgBB dan kelompok perlakuan yang menerima etomidat dan vitamin C 200 mg iv preoperasi. Masing-masing kelompok tersebut selanjutnya diperiksa kadar kortisolnya pre anestesi, 2 jam pasca induksi, 8 jam pasca induksi. Uji statistik Wilcoxon Signed Rank Test dan Paired T Test digunakan untuk membandingkan kadar kortisol di masing-masing kelompok. Uji Mann Whitney dan Independent Sample T Test digunakan untuk membandingkan antar kelompok kontrol dan perlakuan. Hasil: Hasil penelitian menunjukkan pada kelompok kontrol, kadar kortisol preanestesi 244,15 dan 2 jam pasca induksi 185,52 + 35,88 berbeda bermakna (p=0,002). Begitu pula antara kadar 2 jam dengan 8 jam pasca induksi 349,81 + 121,28 (p=0,000). Sedangkan pada kelompok perlakuan, kadar kortisol antara pre anestesi 258,49 (175,45-369,09) dan 2 jam pasca induksi 202,14 + 45,3 tidak berbeda bermakna (p=0,256), begitu pula 2 jam pasca induksi dengan 8 jam pasca induksi 251,39 + 122,91 (p=0,691). Kesimpulan: Dari penelitian ini dapat disimpulkan bahwa pemberian vitamin C 200 mg intra vena 30 menit pre operasi dapat menurunkan efek depresi kortisol oleh pemberian etomidat 0,2 mg/kgBB. Kata kunci : pretreatment, vit c 200 mg, cortisol serum, etomidat