Completed

NCT Number: NCT07397962

Treatment of Histamine Intolerance Using Probiotic Intervention

The goal of this clinical trial is to learn if a probiotic product can lower symptoms in adults with histamine intolerance. Histamine intolerance can cause stomach and bowel problems as well as symptoms such as flushing, itching, headaches, and dizziness. The study will also learn how safe and well tolerated the probiotic is.

The main questions this study aims to answer are:

Does the probiotic lower digestive symptoms linked to histamine intolerance?

Does it lower other common symptoms, such as flushing, itching, headaches, or dizziness?

Researchers will compare the probiotic to a placebo. A placebo is a look-alike powder that contains no active bacteria. This will help determine whether the probiotic works better than no treatment.

Participants will:

Take either the probiotic or the placebo once a day for four weeks

Visit the study center for screening and two study visits

Answer symptom questionnaires

Provide blood samples and urine samples

The study is for adults with symptoms of histamine intolerance. Participation is voluntary, and participants can stop taking part at any time.

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Key information

Conditions

Histamin Intolerance

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Zentrum für klinische Ernährung Stuttgart

Stuttgart, 70599, Germany

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Signed consent form
Symptoms of histamine intolerance (based on medical history)
DAO < 10 U/mL
Age 18-70 years
Willingness to refrain from changing eating habits and physical activity during the study
Sufficient understanding of the German language and sufficient mental state to understand information and instructions related to the study

Exclusion criteria

Lactose intolerance
Fructose malabsorption
Helicobacter pylori infection
Celiac disease
Chronic inflammatory bowel disease
Food allergy with gastrointestinal manifestation
Mastocytosis
Use of antihistamines
Other gastrointestinal diseases or use of gastrointestinal medications, as determined by the investigator
(Planned) change in current medication, as determined by the investigator
Pregnancy and breastfeeding
Inability to take the investigational drug orally
Intolerance to the investigational drug
Admission to a clinic or similar facility due to official or court order
Participation in another clinical trial (currently or within the last 30 days prior to study start)
A health condition or regular medication use that, in the opinion of the investigator, does not allow participation in the study or the evaluation of study parameters or the consumption of the investigational drug (individual decision)

Treatment and study plan

Probio Histamed®, a multi-species probiotic preparation containing Bifid. breve, Bifid. lactis, Bifid. infantis, Bifid. longum, Lact. gasseri, and Lact. rhamnosus (5 x 10⁹ CFU per day)

Dietary Supplement

Multi-species probiotic preparation containing Bifidobacterium breve, Bifidobacterium lactis, Bifidobacterium infantis, Bifidobacterium longum, Lactobacillus gasseri, and Lactobacillus rhamnosus (total dose 5 × 10⁹ CFU per day).

The product is administered as a powder (2 g per day) dissolved in a cold or warm beverage and taken once daily before a meal for four weeks.

Placebo control

Other

maltodextrin

Primary outcomes

Irritable bowel severity scoring system (IBS-SSS)

Time frame: From baseline to the end of the study (4 weeks)

Chang of total score of IBS-SSS, a score ranging from 0 to 500. High values mean high gastrointestinal symptoms.

Secondary outcomes

Facial flushing

Time frame: From baseline to the end of the study (4 weeks)

Facial flushing is measured on a visual analogue scale ranging from 0 to 100 with higher values meaning more pronounced symptoms.
Itching

Time frame: From baseline to the end of the study (4 weeks)

Itching is measured on a visual analogue scale ranging from 0 to 100 with higher values meaning more pronounced symptoms.
Headache

Time frame: From baseline to the end of the study (4 weeks)

Headache is measured on a visual analogue scale ranging from 0 to 100 with higher values meaning more pronounced symptoms.
Dizziness

Time frame: From baseline to the end of the study (4 weeks)

Dizziness is measured on a visual analogue scale ranging from 0 to 100 with higher values meaning more pronounced symptoms.

Other outcomes

Concentration of Diaminooxidase in capillary blood

Time frame: From baseline to the end of the study (4 weeks)
Concentration of Methylhistamine in urine

Time frame: From baseline to the end of the study (4 weeks)

Sponsors and collaborators

Lead sponsor

University of Hohenheim

Other

Collaborators

Lactopia GmbH, An der Römerbrücke 16, 66121 Saarbrücken, Germany

Registry information

Official study title

Treatment of Histamine Intolerance Using Probiotic Intervention - a Randomized Controlled Trial in Adults With Clinical Signs of Histamine Intolerance

Important dates

Study start: 2024
Primary completion: 2025
Study completion: 2025
First posted: Feb 9, 2026
Registry last updated: Feb 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.