Colorectal cancer is the second leading cause of cancer related deaths in the United States; prognosis is projected to increase by 50% within the next 12 years. While chemotherapy is somewhat effective, its notorious for the adverse side effects of weakening the immune system, promoting infection, and organ failure. One significant factor that is undermined is the effects of chemotherapy on the diversity of the microbial communities in the gut. To better understand the drug-host relationship in the human microbiome, we investigated the diversity of bacterial communities obtained from stool sample cultures focusing on the response to 4 common chemotherapeutic drugs- 5-Fluorouracil, Cisplatin, Cyclophosphamide, and Capecitabine, over time. The changes in diversity were tested using DNA extraction and 16s RNA sequencing to compare the communities pre and post treatment. The results obtained revealed that there is a stark difference between the microbial community diversity as a function of time (hours) drugs were administered