Bayer Genuine Aspirin side effects: what 833 FDA adverse event reports show

Bayer Genuine Aspirin · 27 reaction terms · 836 drug–reaction co-reports · data 2026-09-14

Drug class

Nonsteroidal Anti-inflammatory Drug, Platelet Aggregation Inhibitor

FDA label (Established Pharmacologic Class) · compare the class

Who reports

833 reports · 71% serious · 63 with death outcome · 63% female

openFDA FAERS counts, all years, deduplication not applied

Used for

temporarily relieves headache muscle pain toothache menstrual pain pain and fever of colds minor pain of arthritis

FDA label, Indications and Usage

Boxed warning

None in the current label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 18 strongest signals

Labeled adverse reaction 1Labeled (related wording) 1Reporting / coding artifact 8Lab value / disease marker 1Not in label — unassessed 7

What the badges mean

Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 9 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Gastric haemorrhage	25	54.4 37.0–80.1ROR 56.1 · χ² 1,256 / p 2e-275	52.3 EB05 37.2 · IC025 +4.1 3/3 methods agree	Not in label — unassessed	serious PRR 45.5 · 96% consumer	no trial data cached
Incorrect drug administration duration	37	32.7 23.9–44.8ROR 34.2 · χ² 1,105 / p 1e-242	32.2 EB05 24.4 · IC025 +4.0 3/3 methods agree	Reporting / coding artifact	serious PRR 40.2 · 100% consumer	no trial data cached
Product use issue	221	29.8 26.6–33.4ROR 40.2 · χ² 6,168 / p <1e-300	29.7 EB05 26.5 · IC025 +4.6 3/3 methods agree	Reporting / coding artifact	serious PRR 30.4 · 99% consumer	no trial data cached
Gastric ulcer	22	29.1 19.3–44.0ROR 29.9 · χ² 570 / p 4e-126	28.5 EB05 19.8 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 24.8 · 86% consumer	no trial data cached
Drug hypersensitivity	151	19.6 17.0–22.6ROR 23.7 · χ² 2,667 / p <1e-300	19.5 EB05 17.0 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 31.5 · 93% consumer	no trial data cached
Expired product administered	25	19.0 12.9–27.9ROR 19.5 · χ² 408 / p 4e-91	18.7 EB05 13.2 · IC025 +3.1 3/3 methods agree	Reporting / coding artifact	serious n=10 · 100% consumer	no trial data cached
Ulcer	11	17.4 9.7–31.3ROR 17.6 · χ² 154 / p 1e-35	16.2 EB05 8.7 · IC025 +2.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 17.7	no trial data cached
Therapeutic response unexpected	31	17.3 12.3–24.5ROR 18.0 · χ² 462 / p 9e-103	17.1 EB05 12.5 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 40.7 · 100% consumer	no trial data cached
Medication error	37	16.8 12.3–23.0ROR 17.5 · χ² 535 / p 1e-118	16.6 EB05 12.5 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 13.1 · 100% consumer	no trial data cached
Haematemesis (vomiting blood)	14	13.9 8.2–23.3ROR 14.1 · χ² 155 / p 8e-36	12.7 EB05 7.3 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 11.5	no trial data cached
Blood urine present	10	13.2 7.1–24.5ROR 13.4 · χ² 101 / p 4e-24	11.3 EB05 5.6 · IC025 +2.0 3/3 methods agree	Lab value / disease marker	serious PRR 13.7	no trial data cached
Extra dose administered	20	12.6 8.2–19.5ROR 12.9 · χ² 203 / p 2e-46	11.8 EB05 7.6 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious n=12 · 95% consumer	no trial data cached
Haemorrhage	49	11.8 9.0–15.5ROR 12.5 · χ² 476 / p 8e-106	11.5 EB05 8.9 · IC025 +2.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 11.6 · 94% consumer	no trial data cached
Melaena (black stool)	10	11.4 6.2–21.1ROR 11.5 · χ² 85 / p 2e-20	9.3 EB05 4.8 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 9.4	no trial data cached
Drug administration error	14	11.3 6.7–19.0ROR 11.5 · χ² 122 / p 1e-28	9.9 EB05 5.7 · IC025 +2.2 3/3 methods agree	Reporting / coding artifact	serious PRR 26.9	no trial data cached
Intentional product misuse	36	10.4 7.6–14.4ROR 10.9 · χ² 299 / p 3e-67	9.9 EB05 7.3 · IC025 +2.7 3/3 methods agree	Reporting / coding artifact	serious PRR 12.2 · 100% consumer	no trial data cached
Wrong technique in drug usage process	13	8.9 5.2–15.2ROR 9.0 · χ² 83 / p 3e-20	7.3 EB05 4.4 · IC025 +1.8 3/3 methods agree	Reporting / coding artifact	serious PRR 16.5	no trial data cached
Myocardial infarction (heart attack)	51	7.3 5.6–9.5ROR 7.7 · χ² 273 / p 1e-61	6.9 EB05 5.4 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 5.9 · ♀ 39% (drug 63%) · 96% consumer	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Product use issue	221	29.8 26.6–33.4ROR 40.2 · χ² 6,168 / p <1e-300	29.7 EB05 26.5 · IC025 +4.6 3/3 methods agree	Reporting / coding artifact	serious PRR 30.4 · 99% consumer	no trial data cached
Drug hypersensitivity	151	19.6 17.0–22.6ROR 23.7 · χ² 2,667 / p <1e-300	19.5 EB05 17.0 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 31.5 · 93% consumer	no trial data cached
Myocardial infarction (heart attack)	51	7.3 5.6–9.5ROR 7.7 · χ² 273 / p 1e-61	6.9 EB05 5.4 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 5.9 · ♀ 39% (drug 63%) · 96% consumer	no trial data cached
Haemorrhage	49	11.8 9.0–15.5ROR 12.5 · χ² 476 / p 8e-106	11.5 EB05 8.9 · IC025 +2.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 11.6 · 94% consumer	no trial data cached
Medication error	37	16.8 12.3–23.0ROR 17.5 · χ² 535 / p 1e-118	16.6 EB05 12.5 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 13.1 · 100% consumer	no trial data cached
Incorrect drug administration duration	37	32.7 23.9–44.8ROR 34.2 · χ² 1,105 / p 1e-242	32.2 EB05 24.4 · IC025 +4.0 3/3 methods agree	Reporting / coding artifact	serious PRR 40.2 · 100% consumer	no trial data cached
Intentional product misuse	36	10.4 7.6–14.4ROR 10.9 · χ² 299 / p 3e-67	9.9 EB05 7.3 · IC025 +2.7 3/3 methods agree	Reporting / coding artifact	serious PRR 12.2 · 100% consumer	no trial data cached
Therapeutic response unexpected	31	17.3 12.3–24.5ROR 18.0 · χ² 462 / p 9e-103	17.1 EB05 12.5 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 40.7 · 100% consumer	no trial data cached
Expired product administered	25	19.0 12.9–27.9ROR 19.5 · χ² 408 / p 4e-91	18.7 EB05 13.2 · IC025 +3.1 3/3 methods agree	Reporting / coding artifact	serious n=10 · 100% consumer	no trial data cached
Gastric haemorrhage	25	54.4 37.0–80.1ROR 56.1 · χ² 1,256 / p 2e-275	52.3 EB05 37.2 · IC025 +4.1 3/3 methods agree	Not in label — unassessed	serious PRR 45.5 · 96% consumer	no trial data cached
Gastric ulcer	22	29.1 19.3–44.0ROR 29.9 · χ² 570 / p 4e-126	28.5 EB05 19.8 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 24.8 · 86% consumer	no trial data cached
Extra dose administered	20	12.6 8.2–19.5ROR 12.9 · χ² 203 / p 2e-46	11.8 EB05 7.6 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious n=12 · 95% consumer	no trial data cached
Drug administration error	14	11.3 6.7–19.0ROR 11.5 · χ² 122 / p 1e-28	9.9 EB05 5.7 · IC025 +2.2 3/3 methods agree	Reporting / coding artifact	serious PRR 26.9	no trial data cached
Haematemesis (vomiting blood)	14	13.9 8.2–23.3ROR 14.1 · χ² 155 / p 8e-36	12.7 EB05 7.3 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 11.5	no trial data cached
Wrong technique in drug usage process	13	8.9 5.2–15.2ROR 9.0 · χ² 83 / p 3e-20	7.3 EB05 4.4 · IC025 +1.8 3/3 methods agree	Reporting / coding artifact	serious PRR 16.5	no trial data cached

Unlabeled candidate signals

These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.

Gastric haemorrhage — n=25, PRR 54.4
Gastric ulcer — n=22, PRR 29.1
Drug hypersensitivity — n=151, PRR 19.6
Extra dose administered — n=20, PRR 12.6
Myocardial infarction — n=51, PRR 7.3

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Bayer Genuine Aspirin?

In FDA FAERS, the most frequently co-reported reaction terms for Bayer Genuine Aspirin are drug hypersensitivity, myocardial infarction, haemorrhage, gastric haemorrhage, gastric ulcer, extra dose administered. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Bayer Genuine Aspirin have an FDA boxed warning?

No. The FDA label retrieved for Bayer Genuine Aspirin has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Bayer Genuine Aspirin causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID d17834d7-cb3e-6bf2-e053-2a95a90ae5c1, effective 20241230; matched on openfda.generic_name.exact:"BAYER GENUINE ASPIRIN")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 27 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.