| Name | Character | Episodes |
|---|---|---|
| Dirk Martens | Dr. Marcel Plenzdorff | 39 |
| Denise Virieux | Dr. Julia Ritter | 39 |
| Hans Martin Stier | Prof. Dr. Ulrich Bischoff | 39 |
| Francis Fulton-Smith | Dr. Jens Leyendecker | 39 |
| Horst Buchholz | Hubertus Brandt | 2 |
| Ingrid Steeger | Gesa Jaeckel | 1 |
| Rolf Zacher | Harald Kromski | 1 |
| Ulli Kinalzik | Eberhard Senft | 1 |
| Klausjürgen Wussow | Joachim Kamphausen | 1 |
| Dirk Dautzenberg | Ernst Hofer | 1 |
| Judy Winter | Renate Leyendecker | 1 |
| Elisabeth Wiedemann | Hildegard Pawlicek | 1 |
| Siemen Rühaak | Wengert | 1 |
| Jan Niklas | Ben Caspary | 1 |
| Boris Aljinovic | Dr. Karim Busch | 1 |