What the label lists and what reports show
Ascorbic acid side effects
Ascorbic acid's FDA label: “Most common adverse reactions are pain and swelling at the site of infusion (6) To report SUSPECTED ADVERSE REACTIONS, contact McGuff Pharmaceuticals, Inc., toll free at 1-800-603-4795 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.” FAERS holds 23,122 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fatigue (2,337 reports).
- Generic listed
Check it at the source: the ascorbic acid FDA label on DailyMed (effective May 29, 2026, McGuff Pharmaceuticals, Inc.); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions are pain and swelling at the site of infusion (6) To report SUSPECTED ADVERSE REACTIONS, contact McGuff Pharmaceuticals, Inc., toll free at 1-800-603-4795 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
From the label: adverse reactions, continuedADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the labeling: Oxalate nephropathy and Nephrolithiasis [see Warnings and Precautions (5.1)] Hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency [see Warnings and Precautions (5.2)] The following adverse reactions associated with the use of ascorbic acid were identified in the literature. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency reliably or to establish a causal relationship to drug exposure: Administration site reactions: pain and swelling. ASCOR should not be rapidly administered. Rapid intravenous administration (>250 mg/minute) of ASCOR may cause temporary faintness or nausea, lethargy, flushing, dizziness, and headache (the recommended infusion rates of diluted ASCOR solution are 1.3 mg/minute (Pediatric Patients age 5 months to less than 12 months), 3.3 mg/minute (Pediatric Patients age 1 year to less than 11 years) and 33 mg/minute (Adults and Pediatric Patients 11 years and older) [see Dosage and Administration (2.2)]). Acute and chronic oxalate nephropathy have occurred with prolonged administration of high doses of ascorbic acid [see Warnings and Precautions (5.1)]. …
Source: FDA drug label, McGuff Pharmaceuticals, Inc., effective May 29, 2026 (SPL set 388aad52-fc01-4784-9791-1dbc80c69306), via openFDA; the full label on DailyMed
What do FAERS reports show?
23,122 reports list ascorbic acid among the medicines taken, each a report of something that happened, not proof the medicine caused it; 2,611 are coded as a death and 9,238 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 3 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Ascorbic acid: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions