Provides functions for querying, retrieving and analysing protocol- and results-related information on clinical trials from two public registers, the European Union Clinical Trials Register (EUCTR, < https://www.clinicaltrialsregister.eu/>) and ClinicalTrials.gov (CTGOV, < https://clinicaltrials.gov/>). The trial information is transformed and stored in a database (RSQLite or MongoDB, via nodbi). Functions are provided to identify de- duplicated records, to easily find and extract variables (fields) of interest even from complex nesting as used by the registers, and to update previous queries that users retrieved in a database. The package can be used for meta analysis and trend-analysis of the design and conduct as well as results of clinical trials.