FDA Adverse Event Reporting System (FAERS)

The FDA Adverse Event Reporting System (FAERS) is the U.S. Food and Drug Administration’s database of adverse event and medication error reports submitted for drugs and biologics that are already approved and on the U.S. market. It is FDA’s central tool for post-marketing safety surveillance — ongoing monitoring of a product’s real-world safety profile after it has cleared premarket review, as opposed to the safety monitoring that happens inside a clinical trial before approval.

Last verified against FDA primary sources: August 2026.

For research administrators and clinical trial staff, the operationally important distinction is where FAERS sits relative to the trial lifecycle: it is downstream of approval, separate from the investigator/sponsor safety reporting obligations that apply to an investigational product still under an active protocol (governed by ICH GCP and, in the U.S., IND safety reporting under 21 CFR 312.32). An adverse event occurring in an ongoing trial of an unapproved product is not a FAERS report; a report about an approved product already prescribed in routine practice is.

Who Can Report to FAERS, and How

FAERS data comes from two structurally different sources, and understanding which stream a given report came from matters when interpreting the database:

• Mandatory manufacturer reports. Holders of an approved New Drug Application (NDA), Abbreviated New Drug Application (ANDA), or Biologics License Application (BLA) are legally required to submit adverse event reports they become aware of, on regulatory timelines set out in 21 CFR 314.80 (drugs) and 21 CFR 600.80 (biologics) — serious and unexpected events on an expedited (15-day) basis, other events periodically (quarterly for the first three years post-approval, then annually).
• Voluntary reports via MedWatch. FDA’s MedWatch program (FDA Form 3500) lets healthcare professionals, patients, and consumers report a suspected adverse event or product problem directly to FDA, without going through the manufacturer. These reports are voluntary and make up a smaller share of total FAERS volume than mandatory manufacturer reports, but they are an important independent channel — particularly for events a manufacturer may not otherwise learn about.

Both streams flow into the same underlying database, which historically also absorbed FDA’s earlier Adverse Event Reporting System (AERS) predecessor.

FAERS vs. VAERS vs. MedWatch vs. EudraVigilance

These four names get conflated constantly, but each answers a different question. The comparison people are actually searching for — and that no single FDA page lays out side by side — is this:

Dimension	FAERS	VAERS	MedWatch	EudraVigilance
What it is	A database of adverse event and medication error reports	A database of vaccine adverse event reports	A reporting pathway and intake form, not a database in its own right	The EU’s database of suspected adverse reaction reports for medicines
Managing agency	FDA (Center for Drug Evaluation and Research / Center for Biologics Evaluation and Research)	Co-managed by CDC and FDA	FDA’s Office of Surveillance and Epidemiology (the intake channel, not a separate agency)	European Medicines Agency (EMA)
Product scope	Approved drugs and biologics (not vaccines, not devices)	Vaccines only	Drugs, biologics, and medical devices — MedWatch is the front door; reports route to FAERS (drugs/biologics) or MAUDE (devices) behind the scenes	Medicines authorized in the EU/EEA, including vaccines
Reporting basis	Mandatory for manufacturers (21 CFR 314.80 / 600.80); voluntary for clinicians and consumers via MedWatch	Mandatory for healthcare providers and vaccine manufacturers for certain listed events (Vaccine Injury Table, under the National Childhood Vaccine Injury Act); voluntary for patients/caregivers	Not applicable — MedWatch is the submission mechanism used by both mandatory and voluntary reporters	Mandatory for marketing authorization holders and, under EU Regulation (EU) No 536/2014, for clinical trial sponsors reporting SUSARs
Relationship to the others	Receives reports submitted via MedWatch (drug/biologic side); the U.S. counterpart to EudraVigilance	Structurally parallel to FAERS but entirely separate — a vaccine adverse event is a VAERS report, not a FAERS report, even though both are spontaneous-reporting systems run partly by FDA	Feeds FAERS, MAUDE, and other FDA product-safety databases depending on the product type reported	The EU regulatory analog to FAERS; not connected to the U.S. systems, though signal information is sometimes shared internationally
Public data access	FAERS Public Dashboard (interactive) and quarterly ASCII/XML data extract files	CDC WONDER VAERS search interface and downloadable raw data files	N/A — MedWatch itself is not queried; look up the resulting reports in FAERS or MAUDE	European database of suspected adverse drug reaction reports (adrreports.eu) for aggregate public data

The distinction that trips people up most often is FAERS vs. MedWatch: MedWatch is how a report gets submitted; FAERS is where drug and biologic reports end up once they arrive. A single MedWatch Form 3500 submission about a drug becomes a FAERS record. The same form, submitted about a device, becomes a MAUDE record instead — MedWatch itself does not store or publish data.

The distinction that causes the most substantive confusion is FAERS vs. VAERS: they are structurally similar (both spontaneous-reporting, passive-surveillance systems, both carrying the same causation caveat below) but cover entirely different product classes and are governed by different reporting statutes. An adverse event following vaccination is reported to VAERS, not FAERS, even though FDA co-manages both.

How to Search the FAERS Public Dashboard

FDA’s FAERS Public Dashboard is a free, interactive, web-based tool that lets a user query the database by product, event, or time period without needing database or programming skills. A typical research or due-diligence workflow looks like this:

1. Open the FAERS Public Dashboard on fda.gov and choose a search mode — by product (drug/biologic name), by adverse event (using MedDRA preferred terms), or by report characteristics (report type, patient demographics, outcome, report source).
2. Apply filters for date range, since the dashboard is refreshed on FDA’s periodic release cycle and a given quarter’s reports are not final until FDA has completed its own de-duplication and case-processing steps.
3. Read the counts as report counts, not incidence or event-rate estimates — the dashboard has no exposure denominator, so a raw count cannot by itself be turned into a rate.
4. Cross-check any signal of interest against the product’s FDA-approved labeling and, where relevant, published pharmacoepidemiologic literature, rather than treating a dashboard count as a standalone finding.

For anyone new to the interface, FDA also publishes an adverse event glossary and dashboard user guide directly on the same site — worth reading before drawing conclusions from a search.

Quarterly Data Files for Researchers

Alongside the dashboard, FDA publishes downloadable quarterly data extract (QDE) files in ASCII and XML format, intended for researchers, pharmacoepidemiologists, and organizations that want to run their own relational-database analysis rather than query through the web interface. Each quarterly release adds newly processed reports covering that period; because case processing and de-duplication continue after a report first enters the system, cumulative quarterly files are the more complete source for retrospective analysis, while the dashboard is better suited to a quick, current-state look. Both draw from the same underlying report pool. FDA also publishes a data dictionary and readme documentation alongside each quarterly release describing field definitions, coding conventions (including MedDRA terms for the adverse event field), and known caveats — essential reading before importing FAERS data into any analysis pipeline.

What FAERS Does Not Tell You

The single most important interpretive caveat, and one FDA states explicitly about its own database: the presence of an adverse event report in FAERS does not establish that the product caused the event. Reports reflect a suspected association at the time of submission, not a confirmed causal relationship.

FAERS is subject to well-known limitations common to all spontaneous-reporting (passive-surveillance) systems, and these apply equally to VAERS and EudraVigilance:

• No denominator. FAERS does not by itself indicate how many patients were exposed to a product — only how many adverse events were reported. A raw report count cannot be converted into an incidence rate without an independent exposure estimate.
• Underreporting. Only a fraction of adverse events that occur are ever reported, and the fraction varies by event severity, product novelty, and reporter awareness — underreporting is well documented across every spontaneous-reporting system, not specific to FAERS.
• Duplicate reports. The same event can reach FDA more than once — for example, from both the treating clinician via MedWatch and the manufacturer’s own mandatory report — and FDA’s de-duplication process is ongoing rather than instantaneous, so a raw dashboard count can include duplicates not yet resolved.
• Reporting bias. More severe, more novel, or more publicized events are disproportionately more likely to be reported than routine or expected ones, which can distort the apparent relative frequency of different events for the same product.
• Data quality variability. Voluntary reports in particular vary widely in completeness — some include detailed clinical narratives and confirmed diagnoses, others are missing basic fields.

FDA and outside researchers use FAERS data as one input into broader signal-detection and pharmacoepidemiologic analysis — alongside active-surveillance systems with a known denominator, such as FDA’s Sentinel Initiative — not as a standalone causality determination.

FAERS and the Wider Adverse-Event Reporting Landscape

Within FDA’s own remit, FAERS has historically been scoped to drugs and biologics, with medical devices captured separately in MAUDE (Manufacturer and User Facility Device Experience) and vaccine adverse events reported through VAERS, as covered in the comparison above. As of early-to-mid 2026, FDA has reportedly been consolidating FAERS with several of these adjacent legacy systems onto a new unified platform, the Adverse Event Monitoring System (AEMS), intended to eventually process reports for all FDA-regulated product types on one dashboard. The mandatory-vs-voluntary reporting mechanics and legal reporting obligations described above continue to apply to the underlying data either way; given how recent this platform transition is, confirm the current system name and access point directly on fda.gov before citing specifics or linking a live URL.

Frequently Asked Questions

What does FAERS stand for?

FDA Adverse Event Reporting System — the U.S. Food and Drug Administration’s post-marketing safety database for approved drugs and biologics.

Who can submit a report to FAERS?

Manufacturers are required to submit reports they become aware of about their own approved products; healthcare professionals, patients, and consumers may voluntarily submit reports through MedWatch. Both feed the same database.

Does a FAERS report mean the drug caused the adverse event?

No. FDA states explicitly that a report’s presence in FAERS does not establish causation — it reflects a suspected association reported at the time, not a confirmed causal link.

What is the difference between FAERS and VAERS?

FAERS covers approved drugs and biologics; VAERS covers vaccines. They are structurally similar spontaneous-reporting systems — FAERS is FDA-run, VAERS is co-managed by CDC and FDA — but they are separate databases governed by separate reporting rules. A vaccine adverse event is a VAERS report, not a FAERS report.

What is the difference between FAERS and MedWatch?

MedWatch is the reporting pathway (a form and submission process); FAERS is the database that receives drug and biologic reports submitted through it. MedWatch reports about a device go to MAUDE instead — MedWatch itself is not a searchable database.

What is the difference between FAERS and EudraVigilance?

EudraVigilance is the European Medicines Agency’s equivalent database for medicines authorized in the EU/EEA — the closest EU counterpart to FAERS. The two systems are not connected; a report made to one does not automatically appear in the other, and each is governed by its own region’s reporting statutes.

How is FAERS different from IND safety reporting?

IND safety reporting (21 CFR 312.32) applies to an investigational product still under an active clinical trial, before approval. FAERS applies to products already approved and marketed — it is post-market surveillance, not trial-specific safety reporting.

How often is FAERS data updated?

FAERS data has historically been released publicly on a quarterly cycle, through both the interactive public dashboard and downloadable quarterly data extract files; verify current update cadence given FDA’s 2026 platform consolidation described above.

Can I use FAERS data to calculate how common a side effect is?

Not reliably on its own. FAERS has no exposure denominator, so a report count cannot be converted into an incidence rate without an independent estimate of how many patients used the product. Use FAERS for signal detection, not rate calculation.