Background The side effects of chemotherapy, specifically chemotherapy-induced nausea and vomiting, are a concern for patients. To relieve these side effects, antiemetic drugs are recommended. However, some patients report that these drugs are not sufficiently effective. Moreover, patients with chronic disease, including cancer, are increasingly interested in complementary and alternative medicines, and express the desire for nonpharmacological treatments to be used in hospitals. Foot reflexology is a holistic approach that is reported to significantly reduce the severity of chemotherapy-induced nausea and vomiting in patients with breast cancer. Some of the chemotherapy treatments for patients with lung and digestive system cancer are moderately or highly emetic. Objective The primary objective of this study is to assess the benefits of foot reflexology, together with conventional treatments, on the severity and frequency of chemotherapy-induced nausea and vomiting in patients with lung or digestive system cancer. The secondary objectives to be assessed are quality of life, anxiety, and self-esteem. Methods This study is an open-label randomized controlled trial conducted over 22 months (18 months intervention and 4 months follow-up). Eligible participants are patients with a lung or digestive system cancer with an indication for platinum-based chemotherapy. Participants are randomized into two groups: conventional care with foot reflexology and conventional care without foot reflexology. Foot reflexology sessions (30 minutes) are performed on an outpatient or inpatient basis. It was estimated that 40 participants per group will be required. The benefits of foot reflexology will be assessed by comparing the relative change in the severity of nausea and vomiting, as assessed by a visual analogue scale, and the frequency of these side effects between the two groups. The secondary objectives will be assessed with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire; Hospital and Anxiety Depression Scale; and Body Image Questionnaire. Results This study was approved by the regional ethics committee (Île de France X CPP) on April 3, 2018 (No. ID RCB 2018-A00571-54). Enrollment started in June 2018. Data analysis will be performed during the second quarter of 2020 and results will be published in the last quarter of 2020. Conclusions The lack of knowledge regarding the efficacy and safety of foot reflexology limits oncologists to recommend it for this use. This study will provide evidence of the benefits of foot reflexology. If efficacy is confirmed, foot reflexology may be a promising complement to conventional antiemetic drugs. Trial Registration Clinicaltrials.gov NCT03508180; https://www.clinicaltrials.gov/ct2/show/NCT03508180. International Registered Report Identifier (IRRID) DERR1-10.2196/17232