Pneumatosis cystoides intestinalis (PCI) is a rare disease. Its incidence varies from 0.03% to 0.2% in serial autopsy studies. It is defined as air-filled cysts within the wall of the gastrointestinal tract. Primary PCI is extremely rare (15%); in most cases PCI is due to an underlying disease or condition (secondary form – 85%). The pathogenesis of PCI is unknown. Patients either remain asymptomatic or present with non-specific gastrointestinal symptoms. The authors present a case of a patient with mild, chronic diarrhoea. A diagnosis of primary pneumatosis was established. Treatment with antibiotics was initiated. Clinical improvement was achieved. A repeat colonoscopy revealed complete remission.