BACKGROUND : Peritonitis is classified as primary, secondary and tertiary. In primary peritonitis (spontaneous bacterial peritonitis) and continuous ambulatory peritoneal dialysis-associated peritonitis, the source of the infection is not due a breach in the gastrointestinal tract and usually caused by a single organism. Secondary peritonitis ensues, which may be localized and contained or diffuse carrying a high mortality in the absence of surgical intervention and appropriate antimicrobial therapy. Another sequelae of perforated viscus is intra-abdominal abscesses, located in the intra or retroperitoneal space, which occur in partially treated diffuse peritonitis, postoperatively or in localized disease where the omentum has sealed off the perforation and formed an inflammatory barrier. In contrast, secondary peritonitis following perforation of the gastrointestinal tract or an infection originating in an intra-abdominal structure, e.g. gall bladder, pancreas etc. Tertiary peritonitis is an ill-defined entity, which occurs despite adequate treatment of primary or secondary peritonitis. Combination antibiotic therapy has been used to provide the patient with broad-spectrum coverage against the many potential pathogens encountered in abdominal sepsis. Several potential benefits of the clinical use of antibiotic combinations have been advanced. So this study will be conducted to focus on the efficacy of combination of two versus three antimicrobial drug in the management of patients with perforated peritonitis. OBJECTIVES OF THE STUDY: 1.To assess the efficacy of two antimicrobials(Ceftriaxone And Metronidazole) in perforative peritonitis. 2.To assess the efficacy of three antimicrobials(Ceftriaxone, Metronidazole And Amikacin)in perforative peritonitis. 3.To compare the clinical outcome of perforative peritonitis with two and three antimicrobials in the terms of reduction in postoperative infections and hospital stay. MATERIALS AND METHODS SOURCE OF DATA: This is a prospective clinical study conducted on 140 consecutive patients who presented to the surgical department of R. L. Jalappa Hospital and Research Centre, Tamaka, Kolar with peritonitis secondary to hollow viscus perforation. Study period was from December 2015 to June 2017. This is a randomized study and all the patients were divided in two groups. GROUP A: Patients with all odd serial numbers were included in this group and treated with two antimicrobials (Inj Ceftriaxone 1gm IV BD and Inj Metronidazole 500mg IV TID). GROUP B: Patients with all even serial numbers were included in this group and treated with three antimicrobials(Inj Ceftriaxone 1gm IV BD , Inj Metronidazole 500mg IV TID and Inj Amikacin 500mg IV BD). INCLUSION CRITERIA : 1.Patients with peritonitis secondary to hollow viscus perforation. 2.Patients with age >18years and <70years. EXCLUSION CRITERIA: 1.Peritonitis secondary to trauma to the abdomen. 2.Peritonitis secondary to gynaecological interventions like D&C. 3.Peritonitis secondary to malignancies and immuno-compromised state 4.Patients allergic to Ceftriaxone, Metronidazole and Amikacin. 5.Tertiary peritonitis. RESULTS: The clinical outcome in the form reduction in postoperative complications and hospital stay were assessed in 140 patients, in Group A( with the usage of two antimicrobials , Ceftriaxone and Metronidazole) and Group B( with usage of three antimicrobials, Ceftriaxone, Metronidazole and Amikacin). There was decrease in postoperative complications and hospital stay in Group B. The p-value was significant in Group B patients <0.05(0.007). There were 6 deaths, all of them had severe form of peritonitis with massive contamination and delayed presentation to the hospital. This study also revealed that men are commonly affected and duodenal ulcer perforation is the commonest site of perforation. Escherichia coli is the most common organism isolated. CONCLUSION: In our study peritonitis is more common in men compared to women. The most common age group is in between 21 – 40 years in cases of peritonitis with the mean age of 37 years. Duodenal ulcer perforation is the commonest site of perforation. Escherichia coli is the most common organism isolated in the peritoneal fluid. Use of with usage of three antimicrobials, Ceftriaxone, Metronidazole and Amikacin(p<0.05) is beneficial in reduction in postoperative complications and hospital stay when compared to usage of two antimicrobials, Ceftriaxone and Metronidazole which is statistically significant.