Summary Background:e Paul-Ehrlich-Institut (PEI) pub-lished an analysis of reports of adverse drug re-actions (ADRs) in 2001 with test and therapy allergens from the period from 1991 to 2000. Pos-sible risk factors were evaluated for the ADR re-ports classi­ed as “serious”. During the analyzed period, modi­ed semi-depot preparations (aller-goids) induced between 0.01 % and 0.0005 % seri-ous systemic reactions, i. e. one serious ADR occurred in 10,000 to 200,000 injections. No in-formation was provided regarding the respective incidences in relation to the individual companies or preparations. Materials and methods: Within the scope of a 13-year analysis (2001–2013), the serious ADRs were analysed at HAL for the allergoid prepara-tions PURETHAL® Pollen and Mites. As in the analysis of PEI, the frequency of serious ADRs was based on the estimated number of administered
injections. Results:A total of 46 cases with serious ADRs were received. In 26 % of the cases, a serious ADR occurred during initial treatment a˜er the ­rst in-jection. In 82.6 % of the cases, the serious ADR occurred within the 30-minute observation period in the practice. Adrenaline was administered as
emergency treatment in seven cases. Hospitalisa-tions were initiated by the treating physician or by patients themselves in 45 cases. e duration of
the hospital stay varied from a few hours up to three days for further monitoring. Serious ADRs occurred in 11 cases with mites and in 35 cases
with pollen. If it is assumed that there are six in-jections in each vial, this yields an incidence of 0.00061 % (1 : 164,000). e frequency with mites (0.00093 %) was slightly higher than with pollen (0.00055 %).