Sudan black poisoning resulted in methemoglobinemia in a baby with congenital chyloperitoneum.

Treatment of congenital chyloperitoneum is a challenge. Conservative methods may be ineffective. Preoperative visualization of the site of lymphatic leakage is crucial, but radiological imaging is technically complicated and may not provide sufficient information, especially in small patients. To ease the detection of lymphatic leakage during surgery, preoperative feeding with fat-rich formula with Sudan Black has been recommended. However, administration of Sudan Black may result in life-threatening methemoglobinemia and liver damage without any advantage of revealing leakage during surgery. We recommend preoperative feeding with pure fat-rich formula.