The investigations, which I report below and which I began in October 1885 at the suggestion of my esteemed teacher, Professor Dr. med. R. Bohni, aimed to find the active component of white hellebore (Veratrum album)—which was unknown in pure form until then—and to revise previous authors' statements on the alkaloids of this poisonous plant. After four years of continuous work, I mostly achieved this goal, from which the difficulties encountered can be inferred. Previous studies (e.g., Pelletier and Caventou's assumption of Veratrin as the active component, E. Simon's discovery of Jervin, Tobien's identification of Jervin and Veratroidin, and Wright and Luff's findings of Jervin, Rubijervin, Pseudojervin, and amorphous Veratralbin) were reviewed. Two methods were used: the baryta method (extracting with baryta hydrate and ether, yielding Jervin, Protoveratridin, and amorphous decomposition products) and the metaphosphoric acid method (effectively isolating the pure active alkaloid Protoveratrin by precipitating amorphus substances, Jervin, and Rubijervin with metaphosphoric acid, followed by ether extraction). Protoveratrin, a highly toxic crystalline alkaloid (0.3 g per kg of rhizome), was identified as the true active component. Jervin has weak toxicity, while Rubijervin and Pseudojervin are inactive. Previous amorphous alkaloids like Tobien's Veratroidin and Wright and Luff's Veratralbin are likely mixtures of Protoveratrin decomposition products. Wright and Luff's three crystalline bases (Jervin, Rubijervin, Pseudojervin) were confirmed.