Drug & supplement interaction

Fructo-oligosaccharides (fos) + Obinutuzumab

Obinutuzumab brand name: Gazyva.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Fructo-oligosaccharides (fos) and Obinutuzumab in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Obinutuzumab states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Fructo-oligosaccharides (fos) and Obinutuzumab

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Obinutuzumab and Fructo-oligosaccharides (fos) in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Fructo-oligosaccharides (fos) at all — not against Obinutuzumab, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Fructo-oligosaccharides (fos) safety at a glance

Fructo-oligosaccha... overall Use caution Generally well tolerated in food amounts but can cause gas and bloating, especially at higher doses.
Pregnancy Use caution Likely fine in normal food amounts, but supplement-level doses are not well studied, so check with your doctor.
Breastfeeding Use caution Limited safety data for supplement use, so use only with professional guidance.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Obinutuzumab and Fructo-oligosaccharides (fos)? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Fructo-oligosaccharides (fos) and Obinutuzumab May Share a Side Effect

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Constipation Additional detail

    Fructo-oligosaccharides (fos)

    “Orally, FOS may cause flatulence, belching, abdominal pain, intestinal sounds, constipation, and bloating. These symptoms can occur commonly in some patients, but are generally mild at doses under 10 grams per day.”

    Fructo-oligosaccharides (fos) · Natural Medicines adverse-effect record, reported in constipation.

    6 sources cited
    1. 745. Briet F, et al. Symptomatic response to varying levels of fructo-oligosaccharides consumed occasionally or regularly. Eur J Clin Nutr 1995;49:501-7.
    2. 750. Bouhnik Y, Vahedi K, Achour L, et al. Short-chain fructo-oligosaccharide administration dose-dependently increases fecal bifidobacteria in healthy humans. J Nutr 1999;129:113-6. PubMed
    3. 8509. Cummings JH, Macfarlane GT, Englyst HN. Prebiotic digestion and fermentation. Am J Clin Nutr 2001;73:415S-420S. PubMed
    4. 98651. Souza DDS, Tahan S, Weber TK, Araujo-Filho HB, de Morais MB. Randomized, double-blind, placebo-controlled parallel clinical trial assessing the effect of fructooligosaccharides in infants with constipation. Nutrients. 2018;10(11). pii: E1602. PubMed
    5. 107931. Andermann TM, Fouladi F, Tamburini FB, et al. A Fructo-Oligosaccharide Prebiotic Is Well Tolerated in Adults Undergoing Allogeneic Hematopoietic Stem Cell Transplantation: A Phase I Dose-Escalation Trial. Transplant Cell Ther 2021;27(11):932. PubMed
    6. 110710. Dou Y, Yu X, Luo Y, Chen B, Ma D, Zhu J. Effect of Fructooligosaccharides Supplementation on the Gut Microbiota in Human: A Systematic Review and Meta-Analysis. Nutrients 2022;14(16):3298. PubMed

    Obinutuzumab

    Listed in the ADVERSE REACTIONS section of the FDA label for Obinutuzumab. Read the label on DailyMed ›

Reported for Fructo-oligosaccharides (fos) but not commonly for Obinutuzumab: stomach pain and bloating or gas.

Effects for Obinutuzumab come from the ADVERSE REACTIONS section of its FDA label; effects for Fructo-oligosaccharides (fos) come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Obinutuzumab Products Have a Food Rule — Fructo-oligosaccharides (fos) Should Not Break It

At least one FDA label for a product containing Obinutuzumab says to take it on an empty stomach. Most supplements — Fructo-oligosaccharides (fos) included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Obinutuzumab on its own and move Fructo-oligosaccharides (fos) to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Obinutuzumab products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

650–1,000 mg acetaminophen At least 30 minutes before GAZYVA infusion.

From the Dosage and Administration section of the FDA label we read for Obinutuzumab — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

One more smart check

Taking Fructo-oligosaccharides (fos) as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,251 real supplement products containing Fructo-oligosaccharides (fos), each one broken down to its full ingredient list — and combination products often carry several ingredients besides Fructo-oligosaccharides (fos). Even though Fructo-oligosaccharides (fos) itself has no known interaction with Obinutuzumab, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Fructo-oligosaccharides (fos) and Obinutuzumab Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Fructo-oligosaccharides (fos)
Top 25%

#219 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Obinutuzumab
Top 10%

#263 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Fructo-oligosaccharides (fos) reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Fructo-oligosaccharides (fos) and Obinutuzumab records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Fructo-oligosaccharides (fos)

What is Fructo-oligosaccharides (fos)?

  • Digestive and gut health
  • Prebiotic to support good bacteria
  • Constipation relief
  • Calcium absorption support
  • Blood sugar and appetite support

Fructo-oligosaccharides (FOS) are a type of soluble fiber that acts as a prebiotic, meaning they feed the helpful bacteria in your gut. They are generally considered safe for most people in normal food amounts, but higher doses commonly cause gas and bloating. Evidence for many health claims is still limited, so talk with your pharmacist or doctor before using FOS supplements.

Carbohydrate fibers extracted from plants such as chicory root, or made by enzymatic processing of sugars · Powders, capsules, syrups, added to foods and infant formulas, and combined with probiotics in synbiotic products

An interaction check asks whether these two react with each other — it does not ask whether Fructo-oligosaccharides (fos) is a good idea for someone in your situation. Here is what our Fructo-oligosaccharides (fos) record says about it on its own.

Fructo-oligosaccharides (fos): dosing

There is no single official or standardized dose of FOS. Amounts used in studies and products vary widely, often given as a few grams of fiber per day.Because higher amounts increase the risk of gas and bloating, it is best to start low and increase gradually if needed.

From our Fructo-oligosaccharides (fos) monograph — the full record covers uses, side effects and every documented interaction.

Read the full Fructo-oligosaccharides (fos) monograph & all interactions
Medication

About Obinutuzumab Injection

What Is Obinutuzumab Injection Used For?

Brand name: Gazyva

Gazyva is used to treat three conditions. For chronic lymphocytic leukemia (CLL), it is given in combination with chlorambucil in patients who have not been treated before. For follicular lymphoma (FL), it is used either with bendamustine (for patients whose disease came back or stopped responding to a rituximab-based regimen) or with chemotherapy (for previously untreated advanced disease) — in both cases followed by Gazyva alone as maintenance therapy.

Gazyva is also approved for active lupus nephritis — a type of kidney inflammation caused by lupus — in adults who are already receiving standard therapy for the condition.

See full Obinutuzumab Injection drug information
Keep checking

Other Drugs & Fructo-oligosaccharides (fos)

Browse every other medication we’ve checked against Fructo-oligosaccharides (fos) — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
No interaction 2,829 drugs checked — show the list
Evidence & sources

Fructo-oligosaccharides (fos) References

The 6 references that drive our Fructo-oligosaccharides (fos) monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Briet F, et al. Symptomatic response to varying levels of fructo-oligosaccharides consumed occasionally or regularly. Eur J Clin Nutr 1995;49:501-7.
  2. Bouhnik Y, Vahedi K, Achour L, et al. Short-chain fructo-oligosaccharide administration dose-dependently increases fecal bifidobacteria in healthy humans. J Nutr 1999;129:113-6. PubMed
  3. Cummings JH, Macfarlane GT, Englyst HN. Prebiotic digestion and fermentation. Am J Clin Nutr 2001;73:415S-420S. PubMed
  4. Souza DDS, Tahan S, Weber TK, Araujo-Filho HB, de Morais MB. Randomized, double-blind, placebo-controlled parallel clinical trial assessing the effect of fructooligosaccharides in infants with constipation. Nutrients. 2018;10(11). pii: E1602. PubMed
  5. Andermann TM, Fouladi F, Tamburini FB, et al. A Fructo-Oligosaccharide Prebiotic Is Well Tolerated in Adults Undergoing Allogeneic Hematopoietic Stem Cell Transplantation: A Phase I Dose-Escalation Trial. Transplant Cell Ther 2021;27(11):932. PubMed
  6. Dou Y, Yu X, Luo Y, Chen B, Ma D, Zhu J. Effect of Fructooligosaccharides Supplementation on the Gut Microbiota in Human: A Systematic Review and Meta-Analysis. Nutrients 2022;14(16):3298. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Fructo-oligosaccharides (fos) and Obinutuzumab Together: Common Questions

Is it safe to take Fructo-oligosaccharides (fos) with Obinutuzumab?
We do not list a known interaction between Fructo-oligosaccharides (fos) and Obinutuzumab. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Fructo-oligosaccharides (fos) and Obinutuzumab have any of the same side effects?
Yes — our sources link each of them separately to one of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Fructo-oligosaccharides (fos) and Obinutuzumab at the same time of day?
At least one FDA label for a product containing Obinutuzumab says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Obinutuzumab on its own and move Fructo-oligosaccharides (fos) to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Obinutuzumab and Fructo-oligosaccharides (fos)?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.