Chloramphenicol is a semi synthetic, broad spectrum antibiotic derived from Streptomyces venezualae with bacteriostatic activity as it inhibits bacterial protein synthesis.Chloramphenicol remains an important inpatient antibiotic used in treating certain life–threatening infections .We report an adverse drug reaction chloramphenicol induced pancytopenia in a patient with severe traumatic brain injury caused by road traffic accident, treatment was initiated based on literature analysis. He acquired Multi drug resistant Klebsiella pneumoniae. Chloramphenicol was initiated which caused pancytopenia.