Enteritis may cause internal haemorrhoids to bleed in the stool. The cause of enteritis may be the consumption of food contaminated with bacteria, viruses or parasites, which may manifest as diarrhoea, abdominal pain and blood in the stool. These infectious factors may cause secondary infection of internal haemorrhoids and bleeding during defecation. You need to visit a hospital promptly to assess your condition and get early and effective treatment if you suspect enteritis.