This protocol is designed to collect safety and efficacy data on patients that have been or will be treated with eculizumab for STEC-HUS, in the context of the 2011 STEC-HUS epidemic in Germany.

Inclusion Criteria:

1. Patient must be willing and able to give written informed consent/Assent.
2. Adults, adolescents, or pediatric (≥2 months and ≥5kg) patients
3. Patient has been diagnosed with Escherichia Coli Hemolytic-Uremic Syndrome (STEC-HUS)

Exclusion Criteria:

1. Known complement regulatory mutation or family history of complement regulatory mutation
2. Unresolved systemic meningococcal disease
3. 3. Hypersensitivity to eculizumab, to murine proteins or to one of the excipients