We report on a patient with ischemic colitis and another with paralytic ileus, both of whom experienced an acute abdomen after intravitreal injection of bevacizumab (IVB). Case 1 was a 78-year-old woman. Her medical history included surgery for colon carcinoma 10 years earlier. The patient developed acute severe abdominal pain and nausea the day after IVB for retinal vein occlusion with macular edema, and massive lower gastrointestinal bleeding occurred. Ischemic colitis was diagnosed. Case 2 was a 64-year-old man who presented with neovascular glaucoma with proliferative diabetic retinopathy. We performed vitreous surgery on the 9th day after IVB, and we reperformed IVB at the end of the vitreous surgery. On the first postoperative day, severe abdominal distension, vomiting and abdominal pain were observed, and paralytic ileus was diagnosed. It is possible that gastrointestinal disorders are induced after IVB, depending on the patient's background, including for example severe diabetes or a history of surgery for gastrointestinal cancer. Thus, ophthalmologists should apply alternative therapies instead of IVB to patients with severe diabetes mellitus or a history of gastrointestinal cancer.