Provides functions for querying, retrieving and analyzing protocol- and results-related information on clinical trials from two public registers, the 'European Union Clinical Trials Register' ('EUCTR', < https://www.clinicaltrialsregister.eu/>), 'ClinicalTrials.gov' ('CTGOV', < https://clinicaltrials.gov/>) and the 'ISRCTN' (< http://www.isrctn.com/>). Trial information is downloaded, converted and stored in a database ('SQLite' 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.