Chamomile may possess anticoagulant effects based on the presence of coumarin-like compounds within the flower. This randomized, placebo-controlled complete crossover study will investigate the impact of chamomile ingestion on coagulation.

Subjects will be enrolled into three groups in a crossover fashion upon obtaining written informed consent. Baseline laboratory screening assays of anticoagulation will be obtained. The three intervention groups include (1) chamomile tea intake, (2) chamomile extract intake and (3) placebo capsules. Subjects will consume the chamomile or placebo preparations for one week and partake in a one-week washout period between interventions. Screening assays of coagulation will be obtained immediately before and after each intervention week.

Inclusion Criteria:

• Able to provide informed written consent
• Able to withhold use of other chamomile products (teas, lotions, supplements, extracts); will only use study-supplied chamomile products.

Exclusion Criteria:

• Past medical/family history of bleeding/thrombotic disorders (e.g. hemophilia, von-Willebrand disease)

• Chronic medications known to affect hemostasis (anticoagulants, antiplatelet agents, SSRIs, herbal/complementary medicine agents)

• Three or more alcoholic drinks daily

• Sedentary status/ restricted mobility

• Active smoker or quit smoking within one week of screening

• Females who are pregnant, breast-feeding, or lactating

• Scheduled surgical procedure during study period

• Hospitalized patients

• Underweight (BMI < 18 kg/m2) or history of malnourishment

• Active symptoms of a respiratory, dermatologic, urinary, or gastrointestinal infection

• Diagnosed allergy to chamomile

• Severe allergy to ragweed

• Physical inability to consume chamomile tea according to the study dosing schedule

• Prescription usage of an anticoagulant agent such as warfarin, anti-Xa inhibitor, or other novel oral anticoagulants

• ADP antagonist use, including clopidogrel, prasugrel, and ticagrelor

• GPIIb/IIIa inhibitor use, including ticlopidine, eptifibatide

• More than weekly NSAID use (e.g. aspirin, ibuprofen, naproxen)

• Diagnosis of a bleeding-diathesis disorder

• Diagnosis of a hypercoagulable state

• History of elevated INR (including baseline study) or other abnormal bleeding study (PT, aPTT, thrombin time, reptilase time, above the upper limit of normal for Stony Brook Hospital Reference Range) while not taking anticoagulants or herbal supplements listed below

• Active intake of the following herbal supplements at time of study enrollment that may alter baseline coagulation function including:

  • Ginger
  • Garlic
  • Gingko
  • Ginseng
  • Fish oil
  • Black Cohosh
  • Feverfew
  • Valerian
  • Coenzyme Q10
  • Goldenseal
  • St. John Wort

• Baseline CBC with either a hematocrit below 30% or platelet count below 150,000, white blood cell count above 15,000 or less than 3,000.

• Inability to discontinue the aforementioned herbal supplements more than 14 days before enrollment into the study.

• History of estrogen-dependent condition such as uterine fibroids, breast cancer, uterine cancer, or ovarian cancer

• Significant fear of needles or fainting blood draws

• Actively taking cyclosporine

• Patient refusal to participate in study for the allotted study period