CD19 chimeric antigen receptor (CAR) T-cell therapy is associated with potentially life-threatening immunological toxicities. We herein report an 81-year-old woman who experienced multiple perforations in the small intestine 8 days after tisagenlecleucel infusion for relapsed and refractory follicular lymphoma with no gastrointestinal involvement. A pathological examination of the resected small intestine revealed multiple ulcers that formed after resection but without lymphoma involvement. Based on these findings, tocilizumab used for cytokine release syndrome was considered to be associated with these lesions. This case illustrates a previously undescribed but serious sequela of CAR T-cell therapy, calling for relevant personnel to be vigilant about gastrointestinal symptoms.