Drug & supplement interaction

Blood Type Diet + Tofacitinib

Tofacitinib brand names: Xeljanz, Xeljanz XR.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Blood Type Diet and Tofacitinib 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.

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Interaction report

Blood Type Diet and Tofacitinib

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 Tofacitinib and Blood Type Diet in our sources. This does not guarantee that the combination is completely free of risk — research on Blood Type Diet alongside specific medications may be limited.

Worth understanding: our licensed dataset holds no drug-interaction record for Blood Type Diet at all — not against Tofacitinib, 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.

Blood Type Diet is an eating pattern rather than something you take. Ask your pharmacist or doctor before changing how you eat while on a prescribed medicine: some medicines are dosed around meals, and a change in diet can change how they work. 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.

Blood Type Diet safety at a glance

Blood Type Diet overall Use caution The diet itself is generally food-based, but restricting whole food groups may lead to nutrient gaps.
Pregnancy Use caution Restrictive eating plans may limit needed nutrients during pregnancy; check with your doctor first.
Breastfeeding Use caution Avoid overly restrictive versions while nursing and ensure adequate calories and nutrients.

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

Still wondering about combining Tofacitinib and Blood Type Diet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Tofacitinib’s Own FDA Label Lists

This is not an interaction — none of it involves Blood Type Diet. These are the most notable effects listed in the ADVERSE REACTIONS section of Tofacitinib’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you follow Blood Type Diet and take the medicine. 6 of them are worth acting on rather than waiting out — marked below.

  • Low blood sugar Worth acting on
  • Blood clots Worth acting on
  • A low white blood cell count Worth acting on
  • Liver problems Worth acting on
  • A higher chance of infection Worth acting on
  • An allergic reaction Worth acting on
  • Joint pain mentioned in 29.0% of FDA reports for Tofacitinib
  • Headache mentioned in 7.3% of FDA reports for Tofacitinib
  • Diarrhea
  • A skin rash

From the ADVERSE REACTIONS section of the FDA label for Tofacitinib. Read the label on DailyMed › Where a percentage is shown, it is the share of 185,980 voluntary FDA FAERS reports for Tofacitinib that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Blood Type Diet’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Blood Type Diet side to compare — that is a limit of the record, not a statement that Blood Type Diet has no side effects.

Everything else you take

See Every Supplement That Interacts With Tofacitinib

This page covers Blood Type Diet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tofacitinib page lists 184 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Active Hexose Correlated Compound (ahcc) (moderate).

By severity: 3 major · 143 moderate · 38 minor.

From our pharmacist’s overview on the Tofacitinib page

“Supplements deserve genuine care alongside tofacitinib (Xeljanz, Xeljanz XR), a medicine that deliberately dials down the immune system to control conditions like rheumatoid arthritis and ulcerative colitis. Most of the interactions on this page run through the liver enzymes that clear the drug, meaning an herb can push its blood level…”

Reviewed by 2 · Jul 18, 2026

Open the Tofacitinib interaction page

How much people look this up

Where Blood Type Diet and Tofacitinib 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 Blood Type Diet
Steady interest

#1,386 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Tofacitinib
Top half

#938 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 Blood Type Diet reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Blood Type Diet and Tofacitinib records this page draws on were last updated June 22, 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 .
Eating pattern

About Blood Type Diet

What is Blood Type Diet?

  • Weight loss
  • General wellness
  • Heart health
  • Digestive health
  • Reducing inflammation

The Blood Type Diet claims that eating foods matched to your ABO blood type improves health and weight, but good-quality studies have not shown that blood type determines who benefits from a given diet. Any health improvements people see are more likely from simply eating more whole, unprocessed foods. Talk to a pharmacist or doctor before making big changes, especially if you have a health condition.

Eating plan (whole-food diet based on ABO blood type)

An interaction check asks whether these two react with each other — it does not ask whether Blood Type Diet is a good idea for someone in your situation. Here is what our Blood Type Diet record says about it on its own.

Blood Type Diet: dosing

There is no "dose" for the Blood Type Diet — it is an eating pattern, not a pill. Followers are given food lists for their blood type and adjust meals accordingly.If you want to try it, focus on the healthy parts (more whole foods, fewer processed foods) and make sure you still get a full range of nutrients. A pharmacist, doctor, or registered dietitian can help you plan a balanced version and decide whether any supplement, such as a multivitamin, is needed.

From our Blood Type Diet monograph — the full record covers uses, side effects and every documented interaction.

Read the full Blood Type Diet monograph & all interactions
Medication

About Tofacitinib

What Is Tofacitinib Used For?

Brand names: Xeljanz, Xeljanz XR

  • Tofacitinib is used alone or with other medications to treat rheumatoid arthritis (condition in which the body attacks its own joints causing pain, swelling, and loss of function) in adults who are unable to take or did not respond to one or more tumor necrosis factor (TNF) inhibitor medication(s). It is also used to treat psoriatic arthritis (a condition that causes joint pain and swelling and scales on the skin) in adults who are unable to take or did not respond to or tolerate one or more TNF inhibitor medication(s). Tofacitinib is used to treat ulcerative colitis (a condition which causes swelling and sores in the lining of the colon [large intestine] and rectum) in adults who are unable to take or who did not respond to one or more TNF inhibitor medication(s). It is also used to treat polyarticular juvenile idiopathic arthritis (PJIA; a type of childhood arthritis that affects five or more joints during the first six months of the condition, causing pain, swelling, and loss of function) in children 2 years and older who are unable to take or who did not respond to one or more TNF inhibitor medication(s). Tofacitinib is in a class of medications called Janus kinase (JAK) inhibitors. It works by decreasing the activity of the immune system.

See full Tofacitinib drug information
Keep checking

Other Drugs & Blood Type Diet

Browse every other medication we’ve checked against Blood Type Diet — 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

Blood Type Diet References

The 1 references that drive our Blood Type Diet 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. Barnard ND, Rembert E, Freeman A, Bradshaw M, Holubkov R, Kahleova H. Blood Type Is Not Associated with Changes in Cardiometabolic Outcomes in Response to a Plant-Based Dietary Intervention. J Acad Nutr Diet. 2020;S2212-2672(20)31197-7. 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

Following Blood Type Diet While Taking Tofacitinib: Common Questions

Is it safe to follow Blood Type Diet while taking Tofacitinib?
We do not list a known interaction between Blood Type Diet and Tofacitinib. 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.
Does Tofacitinib interact with any supplements?
Yes. Tofacitinib has documented interactions with 184 supplements in our database — Blood Type Diet is not one of them. The Tofacitinib interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Tofacitinib and Blood Type Diet?

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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.