ABSTRACT BACKGROUND: Cancer patients may have gastrointestinal changes that influence nutritional status. OBJECTIVE: To investigate the occurrence of gastrointestinal changes resulting from outpatient chemotherapy treatment in cancer patients. METHODS: In a retrospective longitudinal study, the nutritional status and chemotherapy gastrointestinal changes (nausea, vomit, diarrhea, constipation, mucositis, dysphagia, xerostomia, inappetence, dysgeusia and heartburn) in cancer patients (n=187) were investigated in an outpatient follow-up. For the study of the parameters over time, the generalized estimating equation (GEE) method was used. Kruskal-Wallis, Mann-Whitney tests and Spearman coefficient, at a significance level of 5% were also used. RESULTS: The majority of the patients were female (63.64%) and the mean age was 57.5±12.1 years. The most frequent symptoms were nausea (18.54%); inappetence (18.31%); intestinal constipation (11.58%); diarrhea (7.98%); xerostomia (7.59%) and vomiting (7.43%). The nutritional status did not exhibit any relevant changes (P=0.7594). However, a higher prevalence of eutrophy was observed, followed by overweight; vomiting exhibited a significant difference (P=0.0211). The nausea symptom exhibited a significant difference with a higher prevalence of colorectal neoplasia when compared to breast neoplasia (P=0.0062); as well as vomiting in lung and colorectal neoplasias (P=0.0022), and dysphagia, in head and neck neoplasia, when compared to other neoplasms (P<0.001). There was a statistically significant difference between the number of medical appointments and gender (P=0.0102) and between dysphagia and gender (P<0.0001). CONCLUSION: The study findings enhance the need for signs and symptoms follow up, as well as nutritional status follow up of patients undergoing outpatient chemotherapy.