SummaryThe termdigitalic impregnationhas been used to characterize the effects, clinical as well as electrocardiographic, induced by digitalis treatment. However, in view of the present data of the literature, a more limited significance should be attributed to it, taking into account the balance between digitalis administration to a patient and its inactivation in the body, this balance ensuring the maintenance of an efficient level of the tonicardiac in the organism. On the other hand, when the requisite level is higher than the inactivation rate by the organism, the drug accumulates in the body; if this accumulation exceeds a certain level, varying from one individual to another, intoxication symptoms appear.The variability between therapeutic and toxic doses front one individual to another, have made it imperative to undertake tentative research to determine the requisite level. As far as these drugs are concerned, there is practically no therapeutic effect without risk of toxicity. If toxic manifestations vary from one patient to another, and are characterized either by digestive, neuro-sensitive or cardiac disturbances, or by the association to varying degrees of these various disorders, all preparations of toni-cardiac drugs, however, can involve the same fundamental clinical manifestations. The initial onset of toxic symptoms wouldbe different, in the case of acute and massive intoxication, from those of therapeutic intoxication. Schematically, during the former, digestive symptoms appear very early, soon followed by nervous disorders and finally by cardiac disturbance whereas in the latter, arrhythmia and digestive and neurologic disturbances seem to appear simultaneously.Whatever the case may be, digitalis toxocity is fundamentally characterized by these three kinds of accidents, among which rhythm disturbances are the gravest in view of the risks of lethal collapse they may entail.Prognosis is variable. It does not seem to depend on the ingested dose, but rather on the state of the organism and more particularly on the cardiac and renal states. As a proof, we can mention the prognosis, benign on the whole, of intoxications in the child and in the adult with normal heart. Thrombo-embolic and infectious complications will of course weigh heavily on the prognosis.