What the label lists and what reports show
Balsalazide side effects
Balsalazide's FDA label: “Most common adverse reactions (≥3%) are: headache, abdominal pain, diarrhea, nausea, vomiting, respiratory infection, and arthralgia.” FAERS holds 505 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 diarrhoea (43 reports).
- Generic listed
Check it at the source: the balsalazide FDA label on DailyMed (effective September 9, 2026, Apotex Corp.); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions (≥3%) are: headache, abdominal pain, diarrhea, nausea, vomiting, respiratory infection, and arthralgia.
A table the label prints in its adverse reactions section without a title; its column headings name the groups compared
| Adverse Reaction | 6.75 g/day [N=33] | 2.25 g/day [N=35] | Total [N=68] |
|---|---|---|---|
| Headache | 5 (15%) | 5 (14%) | 10 (15%) |
| Abdominal pain upper | 3 (9%) | 6 (17%) | 9 (13%) |
| Abdominal pain | 4 (12%) | 4 (11%) | 8 (12%) |
| Vomiting | 1 (3%) | 6 (17%) | 7 (10%) |
| Diarrhea | 2 (6%) | 4 (11%) | 6 (9%) |
| Colitis ulcerative | 2 (6%) | 2 (6%) | 4 (6%) |
| Nasopharyngitis | 3 (9%) | 1 (3%) | 4 (6%) |
| Pyrexia | 0 (0%) | 4 (11%) | 4 (6%) |
| Hematochezia | 0 (0%) | 3 (9%) | 3 (4%) |
| Nausea | 0 (0%) | 3 (9%) | 3 (4%) |
| Influenza | 1 (3%) | 2 (6%) | 3 (4%) |
| Fatigue | 2 (6%) | 1 (3%) | 3 (4%) |
| Stomatitis | 0 (0%) | 2 (6%) | 2 (3%) |
| Cough | 0 (0%) | 2 (6%) | 2 (3%) |
| Pharyngolaryngeal pain | 2 (6%) | 0 (0%) | 2 (3%) |
| Dysmenorrhea | 2 (6%) | 0 (0%) | 2 (3%) |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described elsewhere in labeling: Renal Impairment [see Warnings and Precautions ( 5.1 )] Mesalamine-Induced Acute Intolerance Syndrome [see Warnings and Precautions ( 5.2 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.3 )] Hepatic Failure [see Warnings and Precautions ( 5.4 )] Severe Cutaneous Adverse Reactions [see Warnings and Precautions ( 5.5 )] Upper Gastrointestinal Tract Obstruction [see Warnings and Precautions ( 5.6 )] Photosensitivity [see Warnings and Precautions ( 5.7 )] Nephrolithiasis [see Warnings and Precautions ( 5.8 )] Most common adverse reactions (≥3%) are: headache, abdominal pain, diarrhea, nausea, vomiting, respiratory infection, and arthralgia. Adverse reactions in pediatric patients were similar. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Apotex at 1-800-706-5575 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adult Ulcerative Colitis During clinical development, 259 adult patients with active ulcerative colitis were exposed to 6.75 g/day balsalazide in 4 controlled trials.
Source: FDA drug label, Apotex Corp., effective September 9, 2026 (SPL set f12ffa32-d14b-e9d9-e957-2ef08b64e8b4), via openFDA; the full label on DailyMed
What do FAERS reports show?
505 reports list balsalazide among the medicines taken, each a report of something that happened, not proof the medicine caused it; 10 are coded as a death and 107 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 20 reactions below, 11 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?
- Balsalazide: 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