Hello, Blood in stool after appendix surgery is a major matter of big concern with underlying problem of serious consideration. Possible issues may be one of the following: - Unnoticed intestine injury per oepratively - Pre-existing problem of intestine pathology and the appendix inflammation may be part of secondary event of that - Previous history of Inflammatory bowel disease as Ulcerative colitis or Crohn s disease, which may be getting flare up after surgical stress - Side effect of certain medications as antibiotics (less common as that do not produce bloody stool, usually watery) - Pseudomembranous colitis - Others Immediately inform your operating surgeon for further plan of action in this issue. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Bhagyesh V. Patel, General Surgeon