Abstract Background An increasing number of cancer patients are receiving ambulatory chemotherapy to improve their quality of life and reduce medical expenses. During outpatient chemotherapy, adverse events (AEs) occurring at home must be carefully monitored. We investigated the use of our institution’s telephone consultation service that is available to patients and their caregivers for advice on and the management of AEs and complications arising from cancer treatment. Patients and methods Telephone consultants assessed and graded AEs according to the Common Terminology Criteria for Adverse Events (CTCAE). All patient characteristics, AEs, and background factors were analyzed using logistic regression analyses. Results Between August 2011 and August 2012, we included 253 patients and 344 telephone consultations regarding AEs during chemotherapy for analysis in this study. Grade 1 AEs were assessed in 223 consultations (65%); grade 2 AEs, in 90 consultations (26%); and grade 3 AEs, in 31 consultations (9%). A multivariate logistic regression analysis revealed an association between a change in patient schedules and the occurrence of grade 2 or worse AEs (Hazard ratio = 6.58, P