The short answer
German chamomile flower extract could add to clozapine-related sleepiness, but that interaction has not been demonstrated in a clinical clozapine study. The concern is theoretical, and the exact extract matters.
What this answer covers
Oral Matricaria chamomilla (German chamomile) flower extract. Evidence from flowering-top extract is preparation-specific; Roman chamomile, tea and topical use are not equivalent.
- Supplement or preparation
- Matricaria chamomilla (German chamomile) flower extract
- Medication ingredient
- clozapine
Which chamomile is covered
German chamomile may be called Matricaria chamomilla or Matricaria recutita. Roman chamomile is different. A study of a specific flowering-top extract cannot establish the same exposure or effects for tea, another extract or a skin product.
What the clinical study showed
A small trial gave 34 adults with primary insomnia standardized flowering-top extract or placebo for 28 days. Sleep outcomes and adverse events did not differ significantly. People with a history of psychotic disorder and those taking hypnotic medicines were excluded, so this was not a clozapine interaction study.
Why sleepiness is still considered
NCCIH describes the potential interaction with sedatives as theoretical. Clozapine itself can cause sleepiness and impaired coordination. Extra impairment is possible, but the study does not establish its frequency or severity for this combination. Lack of a demonstrated interaction does not prove safety.
No proven timing rule
No clinical evidence here establishes a need to add chamomile, change its amount or separate it from clozapine by a set number of hours. Review the exact oral product with the treating team before using it for sleep. Report troublesome new sleepiness or unsteadiness and avoid driving while impaired.
Evidence and practical considerations
Side effects & toxicity
Additive sedation is a theoretical precaution, not demonstrated clozapine-flower-extract toxicity; the only cited extract trial excluded psychotic disorders.
- Exact scope
- Oral Matricaria chamomilla (German chamomile) flower extract. Evidence from flowering-top extract is preparation-specific; Roman chamomile, tea and topical use are not equivalent. with Oral clozapine, RxNorm 2626 IN.
- Medication form and route
- oral clozapine; oral supplement
What remains uncertain
- No quantified clozapine-specific interaction or validated spacing intervention.
Factors that may matter: Exact preparation; Other medicines and baseline clinical status.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed clozapine.
Clozapine causes sedation and impaired performance, can contribute to falls, and carries dose-related seizure risk. CYP1A2, CYP3A4 and CYP2D6 participate in metabolism. Proposed therapeutic activity includes dopamine D2 and serotonin 5-HT2A receptor antagonism.
How this applies: Medication-specific safety context only; no direct botanical interaction or automatic dose change is established.
No named interaction with these counterparties or measured combined risk.
Source 2: original human clinical study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 34 adults with primary insomnia; lifetime psychotic disorder and current hypnotic medication excluded.
No significant primary sleep benefit or adverse-event difference; reported adverse events mild and transient.
How this applies: Interpret only within the stated preparation, population and endpoints.
No clozapine recipients; one preparation and small study cannot exclude rare interactions or represent every tea or extract.
Source 3: federal supplement safety guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of the named supplement.
Identifies Matricaria recutita and Matricaria chamomilla as German chamomile names, distinguishes Roman chamomile, and describes sedative interactions as theoretical.
How this applies: Supplement-specific guidance interpreted alongside the clozapine label.
General guidance does not quantify a clozapine interaction or establish protective spacing.
Research assessment: · Open full citations ↗
Side effects & toxicity
Possible additional impairment warrants individual review because clozapine causes sedation and the supplement has sedative effects or a stated theoretical sedative-interaction concern; clinical magnitude is unmeasured.
- Exact scope
- Oral Matricaria chamomilla (German chamomile) flower extract. Evidence from flowering-top extract is preparation-specific; Roman chamomile, tea and topical use are not equivalent. with Oral clozapine, RxNorm 2626 IN.
- Medication form and route
- oral clozapine; oral supplement
What remains uncertain
- No quantified clozapine-specific interaction or validated spacing intervention.
Factors that may matter: Exact preparation; Other medicines and baseline clinical status.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed clozapine.
Clozapine causes sedation and impaired performance, can contribute to falls, and carries dose-related seizure risk. CYP1A2, CYP3A4 and CYP2D6 participate in metabolism. Proposed therapeutic activity includes dopamine D2 and serotonin 5-HT2A receptor antagonism.
How this applies: Medication-specific safety context only; no direct botanical interaction or automatic dose change is established.
No named interaction with these counterparties or measured combined risk.
Source 2: original human clinical study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 34 adults with primary insomnia; lifetime psychotic disorder and current hypnotic medication excluded.
No significant primary sleep benefit or adverse-event difference; reported adverse events mild and transient.
How this applies: Interpret only within the stated preparation, population and endpoints.
No clozapine recipients; one preparation and small study cannot exclude rare interactions or represent every tea or extract.
Source 3: federal supplement safety guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of the named supplement.
Identifies Matricaria recutita and Matricaria chamomilla as German chamomile names, distinguishes Roman chamomile, and describes sedative interactions as theoretical.
How this applies: Supplement-specific guidance interpreted alongside the clozapine label.
General guidance does not quantify a clozapine interaction or establish protective spacing.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Prepared evidence-based article with explicit preparation and endpoint limits. | |
| Research summary published |
Article revision: 8752f58ffe3624ad
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.