Introduction: Uncontrollable nausea and vomiting can cause delay in chemotherapy period and a general decrease in patient’s quality of life. Since matricaria chamomilla is believed to be effective in reducing nausea and vomiting, the present study was aimed at determining the effect of its extract on the severity of nausea and vomiting caused by chemotherapy in Zahedan’s Social Security Hospital. Materials and methods: The present single-blind clinical trial was carried out on the patients receiving chemotherapy in Chemotherapy Wards of Zahedan’s Hospitals in 2015. In doing so, 60 patients were selected through convenience sampling and assigned into an intervention group and a control one. Two hours before chemotherapy, the intervention group was given matricaria chamomilla extract while the control patients were given distilled water as placebo. Nausea rate was measured using Visual Analogue Scale (VAS) 0, 2, 6, and 12 hours after chemotherapy. Results: In the beginning of the study, there was no significant difference between the two groups in terms of their mean scores of nausea (P=0.4); however, 2 hour after chemotherapy had been carried out, nausea score increased in both groups, such that it was significantly higher in the control group than the intervention group (P=0.034). After 6 and 12 hours, the mean scores of nausea in both groups declined; however, the control patients’ mean score was constantly and significantly higher than that of the intervention group. There was no significant difference between the two groups in regard to vomiting (P>0.05). Conclusion: The results of the study indicated that consuming matricaria chamomilla extract can reduce nausea caused by chemotherapy while it has no effect on vomiting.