Det aktive indholdsstof i Caelyx er doxorubicin hydrochlorid, et cytotoksisk antracyclin- antibiotikum, der er udvundet af Streptomyces peucetius var. caesius.
The active ingredient of Caelyx is doxorubicin hydrochloride, a cytotoxic anthracycline antibiotic obtained from Streptomyces peucetius var. caesius.