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

Subjects will be enrolled into two groups in a crossover fashion upon obtaining written informed consent. The two intervention groups include (1) chamomile tea intake and (2) chamomile extract intake. Subjects will consume a single preparation of chamomile tea or extract capsule, and partake in a minimum of three days washout period between interventions. Screening assays of coagulation will be obtained immediately before the ingestion of chamomile, two hours after ingestion, and four hours after ingestion over the course of a single day.

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 for duration of study
• Able to withhold intake of solid food at least 6 hours before intake of the chamomile preparation
• Able to withhold intake of clear liquids at least 2 hours before intake of the chamomile preparation

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 study period

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

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

• 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 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

• Active intake of chamomile extracts or teas at time of study enrollment

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

• Significant fear of needles or fainting blood draws

• Actively taking cyclosporine

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