Purpose of the thesis: The primary aim of this thesis was to investigate the efficacy of different thyrostatic drugs, in particular propylthiouracil (PTU) and thiamazole, in the treatment of thyrotoxic crisis. The objective of the study was to find out which drug responds most quickly and to investigate how factors such as age, BMI, smoking status, gender and previous illnesses for example Graves' disease influence the treatment results. The study examined how additional therapies, including glucocorticoids, beta blockers and iodine supplements, affected the effectiveness of these treatments. Methods: The methology of this thesis included a study of a retrospective analysis of 70 patients treated for thyrotoxic crisis at the Bezirkskrankenhaus Oberfranken/Südthüringen Klinikum Coburg from 2018 to 2022. The patients were divided into two groups: those treated with PTU (32 patients) and those treated with thiamazole (38 patients). Data collection included thyroid function tests (TSH, FT3, FT4), heart rate, weight, height, smoking habits and medical history. The severity of the crisis was assessed using the Burch-Wartofsky score and statistical analyses were performed to compare the treatment outcomes of the two drug groups. Results: The study showed that PTU led to a faster normalization of thyroid hormone levels compared to thiamazole. Patients in the PTU group achieved normalization of FT3 in an average of 5.23 days and FT4 in 7.38 days. In contrast, patients in the thiamazole group required 8.18 days for FT3 normalization and 10.5 days for FT4 normalization. Independent variables were found to have a significant impact on treatment duration, with men, older patients and smokers requiring more time for hormone normalization. The study also found that 60% of the total population had pre-existing thyroid conditions. Furthermore, the study concludes that PTU causes a faster normalization of thyroid hormone levels in patients with a thyrotoxic crisis than thiamazole. The results underline the importance of individualized treatment strategies, taking into account factors such as gender, BMI, smoking status and age, to optimize patient outcomes. The study advocates for further research to understand the mechanisms behind these differences and to validate the results in larger, more diverse populations.