diff --git a/app.yaml b/app.yaml
index 1fead0b..0feff6e 100644
--- a/app.yaml
+++ b/app.yaml
@@ -17,7 +17,7 @@ kafka:
 fhir:
   medication:
     profile: https://www.medizininformatik-initiative.de/fhir/core/modul-medikation/StructureDefinition/Medication
-    system: https://miracum.org/fhir/NamingSystem/identifier/P21SurrogateMedicationId
+    system: https://fhir.diz.uni-marburg.de/sid/medication-id
   medication_statement:
     profile: https://www.medizininformatik-initiative.de/fhir/core/modul-medikation/StructureDefinition/MedicationStatement
     system: https://fhir.diz.uni-marburg.de/sid/medication-statement-id