If constipation or diarrhea starts after you begin a fiber supplement, check the product directions, serving size, and how quickly you increased the amount. A sudden increase can cause digestive symptoms, but timing alone does not prove the supplement is the cause. Follow the label or prescription, and contact a clinician or pharmacist before changing a prescribed treatment or if symptoms persist or concern you.
First, check how you are taking the supplement
- Confirm the product and form, serving size, and frequency. Do not take more than the package or prescription directs.
- If you use psyllium powder or granules, mix each dose with at least 8 ounces (240 mL) of liquid immediately before taking it, as MedlinePlus advises. Follow the specific product or prescription directions.
- Consider whether you recently made a large increase. Adding fiber gradually gives your digestive system time to adjust; a rapid increase can cause gas, bloating, cramps, or diarrhea.
- Write down the product, amount, timing, symptoms, and any other medicines or recent changes to your diet. This can help a clinician or pharmacist assess what may be contributing.
Do not assume that more fiber is always better. NIDDK gives 22 to 34 grams of dietary fiber per day as a general adult range that varies by age and sex; that figure is not a supplement dose, and individual needs can differ.
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If the problem is constipation
Check whether you are taking the product with the amount of liquid its directions require and whether you increased fiber quickly. General constipation self-care includes adequate fluids with fiber, regular physical activity, and allowing time to respond when you feel the urge to have a bowel movement. A health professional can help assess whether the supplement, another medicine, hydration, or a different cause may be involved.
Seek prompt medical attention for constipation with rectal bleeding or blood in the stool, constant abdominal pain, inability to pass gas, vomiting, or fever. NIDDK also advises contacting a doctor for lower back pain or unexplained weight loss, and if symptoms do not go away with self-care.
#1 Best Overall
- INTESTINAL HEALTH*/HELPS MAINTAIN REGULARITY*: Psyllium has the ability to swell up to 50 times its initial volume when added to liquid. This bulking action can play an important role in maintaining regularity and gastrointestinal health*
- NATURAL SOLUBLE FIBER: Surveys have shown that the fiber content of the American diet is typically about half of government recommended levels. NOW Psyllium Husk capsules can be a convenient way to increase the intake of dietary fiber*
- CERTIFICATIONS/CLASSIFICATIONS: Non-GMO Project Verified, Kosher, Vegan/Vegetarian, Soy Free, Made without Gluten, Corn Free, Keto Friendly
- GMP Quality Assured: NPA A-rated GMP certification means that every aspect of the NOW manufacturing process has been examined, including our laboratory/testing methods (for stability, potency, and product formulation)
- Founded in 1968 by Elwood Richard, NOW is one of the largest independent, family- and employee-owned manufacturers of natural products
If the problem is diarrhea
Diarrhea can cause loss of fluids and electrolytes. Replace them with water and electrolyte-containing liquids; oral rehydration solutions are another option. NIDDK advises older adults and people with a weakened immune system, diabetes, kidney disease, or another health condition to ask a doctor before using an oral rehydration solution.
Talk with a doctor right away if you have signs of dehydration, frequent vomiting, severe abdominal or rectal pain, blood or pus in stool, or black, tarry stool. For adults, NIDDK also identifies diarrhea lasting more than two days, a high fever, or six or more loose stools in a day as reasons to seek medical advice. Pregnant people, adults over 65, people taking antibiotics, and people with weakened immune systems have a higher risk of complications and should keep in touch with a doctor.
Rank #2
- FEEL WHAT LIGHTER FEELS LIKE by helping promote regularity when you make Metamucil fiber capsules a part of your daily routine.*
- ONLY TWO INGREDIENTS. Metamucil Daily Fiber Capsules are made with only two ingredients, including psyllium husk fiber.
- HELPS SUPPORT HEALTHY BLOOD SUGAR LEVELS. Taking Metamucil fiber capsules with each meal helps maintain healthy blood sugar levels*
- HELPS PROMOTE HEART HEALTH BY LOWERING CHOLESTEROL. Taking Metamucil fiber capsules helps lower your cholesterol
- CONVENIENT PSYLLIUM FIBER CAPSULES. Metamucil’s psyllium husk fiber capsules are easy to take on the go.
When to ask before changing your treatment
Talk with a clinician or pharmacist before stopping or changing a prescribed regimen because you suspect a supplement or medicine is contributing. Get professional advice before using psyllium if you have trouble swallowing, a history of intestinal blockage, relevant health conditions, or take medicines that could interact. A pharmacist can review the exact product and your medication list.
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A bowel change can also be related to other medicines, a diet change, dehydration, or an unrelated illness. Seek professional advice for a persistent or concerning change rather than treating the timing of symptoms as proof of the cause.
Quick Recap
Best Value
- EXCELLENT SOURCE OF FIBER: Soluble fiber from foods such as psyllium seed husks, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.
- DIRECTIONS: Vigorously mix 1 level tablespoon daily into at least 12 oz. of water or juice and consume immediately
- 6 GRAMS OF SOLUBLE FIBER: A serving of psyllium husk powder supplies 6 grams of the 7 grams soluble fiber necessary per day.
- GMP Quality Assured: NPA A-rated GMP certification means that every aspect of the NOW manufacturing process has been examined, including our laboratory/testing methods (for stability, potency, and product formulation).
- Packaged in the USA by a family owned and operated company since 1968.
Rank #4
- INTESTINAL HEALTH*/HELPS MAINTAIN REGULARITY*: Psyllium has the ability to swell up to 50 times its initial volume when added to liquid. This bulking action can play an important role in maintaining regularity and gastrointestinal health*
- NATURAL SOLUBLE FIBER: Surveys have shown that the fiber content of the American diet is typically about half of government recommended levels. NOW Psyllium Husk capsules can be a convenient way to increase the intake of dietary fiber*
- CERTIFICATIONS/CLASSIFICATIONS: Non-GMO Project Verified, Kosher, Vegan/Vegetarian, Soy Free, Made without Gluten, Corn Free, Keto Friendly
- GMP Quality Assured: NPA A-rated GMP certification means that every aspect of the NOW manufacturing process has been examined, including our laboratory/testing methods (for stability, potency, and product formulation)
- Founded in 1968 by Elwood Richard, NOW is one of the largest independent, family- and employee-owned manufacturers of natural products
Rank #3
- PSYLLIUM HUSK FIBER: Each 2-capsule serving provides 1,450 mg of psyllium husk, a source of dietary fiber, in a convenient capsule format
- REGULARITY & DIGESTIVE SUPPORT: Psyllium husk absorbs water and forms a gel to help support regularity, intestinal health, and digestive health when taken with adequate water
- A STRAIGHTFORWARD FIBER SUPPLEMENT: Pre-measured psyllium fiber capsules offer a simple way to add dietary fiber without preparing another drink mix
- NO POWDER MIXING: A convenient alternative to psyllium husk powder—no scooping, stirring, or measuring; take the capsules with a full glass of water
- 240 CAPSULES, 120 SERVINGS: For occasional use only. Take 1–2 capsules twice daily with at least 8 oz of water, or as directed by a healthcare professional
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