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Drug side effects

folic acid Side Effects

The reactions most often reported to the FDA for folic acid (also sold as Folvite), with demographics, serious outcomes, and reporting trends.

Data updated 2026-05-15

241,433
FAERS reports

Data from the FDA Adverse Event Reporting System (FAERS), 2003 to 2025. A FAERS report records a temporal association, not proof of cause. See our methodology for how figures are compiled and de-duplicated.

The most commonly reported side effects of folic acid come from 241,433 reports to the FDA, broken down here by frequency, patient demographics, and serious outcomes.

This page analyzes 241,433 reports to the FDA Adverse Event Reporting System (FAERS) for folic acid (Folvite): the reactions reported most often, who reported them, serious outcomes such as hospitalization, and year-over-year trends. A FAERS report does not prove the drug caused the effect, and report volume tracks how widely a drug is used, not how likely an effect is for any one person. Educational information, not medical advice.

Total Reports

241,433

Reports Mentioning Death

22,144

9.2% of reports — not proof the medicine caused the death

Hospitalizations

87,188

36.1% of reports

Top Indication

Product Used For Unknown Indication

Most Reported Adverse Reactions

FATIGUE
23,332
PAIN
23,054
ARTHRALGIA
19,495
RHEUMATOID ARTHRITIS
17,528
NAUSEA
15,633
HEADACHE
14,211
DIARRHOEA
14,142
RASH
13,595
DYSPNOEA
13,157
ALOPECIA
11,667
ABDOMINAL DISCOMFORT
11,665
JOINT SWELLING
11,529
CONDITION AGGRAVATED
11,126
VOMITING
10,810
PNEUMONIA
10,795
PYREXIA
10,612
PAIN IN EXTREMITY
10,574
SYSTEMIC LUPUS ERYTHEMATOSUS
9,863

Who Reports Side Effects

Gender Distribution

Female 152,545 (68%)
Male 70,365 (32%)
Unknown 340

Age Distribution

0-17 5,548 (3%)
18-44 31,217 (20%)
45-64 61,818 (39%)
65-74 35,410 (22%)
75+ 25,879 (16%)

Reporting Trend by Year

2003 2025

Reactions in Death Reports

Top reactions reported in 22,144 reports where death was an outcome. These are voluntarily reported and do not establish causation.

Reaction Reports
DEATH 5,981
PNEUMONIA 2,632
GENERAL PHYSICAL HEALTH DETERIORATION 2,540
FATIGUE 2,504
DIARRHOEA 2,332
VOMITING 2,210
DYSPNOEA 2,194
RHEUMATOID ARTHRITIS 2,150
RASH 2,134
HYPERTENSION 2,133
SYSTEMIC LUPUS ERYTHEMATOSUS 2,117
TYPE 2 DIABETES MELLITUS 2,082
PAIN 2,077
HYPOAESTHESIA 2,027
GLOSSODYNIA 2,014
INFUSION RELATED REACTION 2,006
DUODENAL ULCER PERFORATION 1,998
ARTHRALGIA 1,997
FIBROMYALGIA 1,992

Reactions in Hospitalization Reports

Top reactions in 87,188 reports where hospitalization was an outcome.

Reaction Reports
FATIGUE 7,987
PNEUMONIA 7,501
PAIN 7,490
DYSPNOEA 7,236
ARTHRALGIA 6,934
DIARRHOEA 6,899
NAUSEA 6,613
PYREXIA 6,481
VOMITING 6,128
FALL 5,610
RHEUMATOID ARTHRITIS 5,556
HEADACHE 5,140
ASTHENIA 5,132
RASH 5,102
CONDITION AGGRAVATED 4,886
MALAISE 4,867
DIZZINESS 4,620
GENERAL PHYSICAL HEALTH DETERIORATION 4,163

Compare folic acid vs ascorbic acid →

What the FAERS Data Reveals About folic acid Side Effects

The FDA Adverse Event Reporting System (FAERS) contains 241,433 voluntary reports linked to folic acid and its brand equivalents (Folvite), spanning 2003 through 2025. Of those, 22,144 (9.2%) listed death as an outcome and 87,188 (36.1%) involved hospitalization. The most common indication reported alongside adverse events was Product Used For Unknown Indication.

Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 68% were female and 32% male; age distribution skews toward 45-64, with 61,818 reports in that bracket. The single most reported reaction is fatigue with 23,332 submissions, followed by pain and arthralgia.

How to read these numbers

FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice, speak with a licensed clinician about any side-effect concerns.