PhysioNet

PhysioNet is maintained by MIT's Laboratory for Computational Physiology and has spent more than two decades as a home for reproducible medical research data. Its catalogue runs from physiological waveforms such as heart traces (ECG) and brain activity (EEG) to structured clinical databases, medical imaging, and the open-source software used to analyse them. It is also where several landmark datasets are distributed, most famously the MIMIC critical- care databases of de-identified intensive-care records.

You work through the catalogue project by project: browse by topic, open a project page, and download its files, documentation, and licence from one place. Formats vary a lot between projects, from CSV tables and free-text clinical notes to specialised waveform files, so expect to write a loader per dataset rather than a single pipeline. For a clinical RAG system, the text- rich datasets are the obvious raw material, the discharge summaries, radiology reports, and progress notes inside MIMIC among them. Clean and de-identify the notes, chunk them sensibly, and embed them next to the structured fields you want to filter on.

PhysioNet earns its place when you need genuine clinical language and physiological measurements rather than general medical prose. It suits research prototypes, clinical-decision-support experiments, and any system that must reason over real, de-identified patient records.

Access is the thing to plan for. Plenty of datasets download openly, but the sensitive ones, MIMIC included, require you to become a credentialed PhysioNet user, which means completing recognised human-subjects research training and signing a data-use agreement that can take days or weeks to clear. Licences differ from one project to the next and several are research-only, so commercial use is not a given: read the terms on each page before you build, and never pass the underlying records to a third-party service in a way the agreement forbids.

For openly licensed drug and trial metadata to sit alongside it, ClinicalTrials.gov and DrugBank complement it well. PhysioNet is the source to reach for when you specifically need patient-level clinical records and signals.