Pneumatosis cystoides intestinalis (PCI) is a relatively rare condition in which gas is found as a linear or cystic form in the submucosa or subserosa of bowel wall. PCI is usually found incidentally on an imaging study. Treatment is usually conservative including oxygen and antibiotics therapy. So far, etiology and pathogenesis of PCI remain uncertain. PCI is associated with various medical conditions including various pulmonary diseases, connective tissue diseases, and endoscopic procedures. However, there are only few reports on lactulose causing PCI in patients with cirrhosis. Oral lactulose or enema is one of the main treatment modalities in hepatic encephalopathy. Here, we report a case of PCI which was found during the treatment with lactulose therapy in a patient with liver cirrhosis and hepatic encephalopathy.