Humans and their microbiota are in a symbiotic relationship. It is known that microbiale residents within and on human bodies have the potential to impact host physiology in both healthy and disease states. To date, little is known about the potential influence of the gut microbiome on the onset of nausea symptoms among cancer patients undergoing chemotherapy treatment. Chemotherapy-induced nausea (CIN) is a serious and common side effect. The CIN presentation is often coupled with other symptoms such as fatigue, sleep disturbance, depression, and anxiety. These symptoms both on an individual and collective level, cause negative impacts on patients’ health outcome as they challenge patients’ ability to tolerate and comply with chemotherapy. To understand the association between gut microbiome and CIN, we applied 16S rRNA amplicon sequencing to characterize the gut microbiome of breast cancer patients who reported nausea symptoms and those who reported no nausea symptoms. We hypothesize that the gut microbiome of patients who reported nausea symptoms is distinct from patients who reported no nausea. Our findings support this hypothesis, as the gut microbiome of nausea case was distinct from the no nausea cases. Specifically, we observed decreased abundance of Bacteroidetes in patients who reported nausea, while patients who reported no CIN had constant or increased abundance of Bacteroidetes. Overall, we showed that changes in the gut microbiota have an association with the occurrence of CIN symptoms among breast cancer patients receiving chemotherapy. These findings provide preliminary data for extensive research on the role of gut microbiome in CIN in the future.