Owing to its controlling action upon the heart it acts secondarily as a diuretic and was first employed in dropsy for this purpose by the Russians. Like digitalis, it is useful in those cases of dropsy where the cardiac debility is such that there is imperfect circulation through the organ itself, and where there is evidence of obstruction. Palpitation and irregular movements, dyspnoea, diminished renal action with increase of solids in the urine, hepatic fullness and engorgement, and oedema, are usually symptoms of this form of cardiac inefficiency. The cases of dropsy benefited, therefore, are those of cardiac origin with feeble circulation and diminished blood pressure. In small doses convallaria is a tonic to the heart, strengthening its action.
Cardiac excitation is relieved by moderate doses, while large doses increase the heart action.
Mitral insufficiency , with the attendant dyspnoea and palpitation, is considered as a proper condition for the exhibition of convallaria. When the favorable action upon the heart and vessels begins the heart-beats become slower, normal rhythm is established, heart power is increased, arterial pressure is augmented, respiration deepened, and the suffocative sensation, with the distressing and painful desire for air, is dispelled. Convallaria should be thought of in the cardiac debility following severe and exhaustive diseases, such as typhoid fever, la grippe , etc. It tends to promote a normal circulation, and relieves that sense of praecordial faintness which is apt to follow prostrating conditions. Convallaria has had no bad effects upon the cerebro-spinal tract, nor upon the digestive organs.