Background: Since 2018/2019, three S3 treatment guidelines (GL) for alcohol-, pharmaceutical-, and tobacco-related disorders have been developed and approved in Germany. In addition to the scientifically correct procedures for developing GL, the collection and evaluation of potentially competing interests (CI) are central to the quality of the GL. Aims: Description of methods for processing potential CI and of results. Methods: Data on 11 themes concerning potential financial and non-financial CI from 217 participants have been collected using an existing questionnaire. Analysis took place by partly drawing on existing criteria, partly utilizing a newly developed coding system for information on potential CI, as well as a newly developed system of topic-related voting limitations. Findings: 69 participants (32 %) had no CI, 48 (22 %) had a CI with limited relevance (leading position), 86 (40 %) had a moderate level CI (abstention from voting) and an additional 14 (6 %) had a high-level CI (exclusion from session). Through the application of the new system of topic-related voting limitations, it was possible for 60 % to 90 % of the 148 contributors with a limitation to still participate, depending on the GL topic. Conclusions: The assessment system for potential CI and related exclusion measures reached a high level of acceptance; a re-evaluation was necessary in only about 5 % of cases. The statistical indicators differed considerably between the different GL. This requires further methodological analyses and better instructions using examples, particularly with regards to non-financial CI.