In six healthy volunteers the bioavailability of alpha-acetyldigoxin in solution and tablet form was compared with a tablet which in addition to alpha-acetyldigoxin contained the DH-ergot alkaloid Hydergine in identical galenic formulation. After a single dose, bioavailability was measured from the areas under the plasma level time curves and from the cumulative amount of digoxin excreted into the urine. The addition of Hydergine did not change the plasma level/time profile and the bioavailability of alpha-acetyldigoxin. When this parameter was compared to the solution, a relative bioavailability of approximately 80% could be calculated for both tablets. Relating this data to a previously published infusion experiment, their absolute bioavailabilities amounted to about 70%.