psyllium
Brand names: Metamucil
Metamucil is a fiber supplement that helps you have regular bowel movements. It is a bulk-forming laxative.
What it does
Metamucil is used to relieve constipation that happens from time to time.
Common side effects
Changes in bowel habits, Minor bloating
Key warnings
Taking this product without enough liquid may cause choking.
How It Works
Metamucil contains psyllium, a type of fiber. This fiber absorbs water in your intestines. This makes your stool softer and easier to pass.
How to Take It
Adults and children 12 years and older should mix 1 rounded teaspoon into 8 ounces of liquid. Drink it right away. You can take this up to 3 times a day when you are constipated. If you are taking other medicines, take Metamucil 2 hours before or after.
Pregnancy & Breastfeeding
Talk to your doctor before taking Metamucil if you are pregnant or breastfeeding. They can advise you on whether it is safe for you.
Missed Dose
If you miss a dose, take it as soon as you remember. Do not take more than the recommended daily amount.
Storage
Keep this product out of reach of children.
Serious Warnings
Taking this product without enough liquid may cause choking. Be sure to mix with at least 8 ounces of water or other fluid and drink promptly.
Common Questions
How quickly will Metamucil work?
Can children under 12 take Metamucil?
What happens if the mixture gets too thick?
Can I take Metamucil with other medications?
How much liquid should I use?
What should I do if I experience bloating?
Can I take Metamucil every day?
What is the active ingredient in Metamucil?
Does Metamucil have a taste?
What should I do if Metamucil doesn't work?
What are the common side effects of psyllium?
What drug class is psyllium?
Is psyllium safe during pregnancy?
Related Medications in Bulk-Forming Laxative
Other drugs grouped near psyllium — same-class peers and common alternatives.
alosetron
Lotronex
Alosetron (Lotronex) is a medicine for women with severe diarrhea-predominant irritable bowel syndrome (IBS).
Compare with psyllium →
aprepitant
Emend
Aprepitant (Emend) is a medicine that helps prevent nausea and vomiting.
Compare with psyllium →
bisacodyl
Dulcolax
Bisacodyl is a medicine that helps you have a bowel movement.
Compare with psyllium →
bismuth subsalicylate
Pepto-Bismol
Bismuth subsalicylate (Pepto-Bismol) is a medicine that can treat diarrhea and upset stomach.
Compare with psyllium →
cimetidine
Tagamet
Cimetidine (Tagamet) reduces stomach acid.
Compare with psyllium →
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What the FDA Data Shows for psyllium
The FDA label for psyllium (sold under brand names such as Metamucil) classifies it as an over-the-counter product in the Bulk-Forming Laxative class. Metamucil is used to relieve constipation that happens from time to time. Official labeling lists 2 commonly reported side effects, including Changes in bowel habits, Minor bloating.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. Voluntary reports accumulate over the lifetime of a drug and reflect wide-ranging clinical use. Interaction data is drawn directly from FDA-approved prescribing information. Acquisition-cost data is surveyed weekly by CMS and updated as manufacturers report changes.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: January 30, 2025
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages