Chamomile tea shows real biological activity that could, in theory, help with blood pressure, but there is no direct clinical trial proving it lowers blood pressure in people with hypertension. The most compelling evidence comes from laboratory studies showing that chamomile compounds relax blood vessels, and from small human trials in people with type 2 diabetes where chamomile tea improved cholesterol and blood sugar markers that are themselves linked to cardiovascular risk. The gap between these findings and a confident recommendation is wider than most wellness websites acknowledge.
What Happens in Blood Vessels
The strongest mechanistic case for chamomile and blood pressure comes from studies on isolated blood vessels. Apigenin, the flavonoid most associated with chamomile, triggers relaxation of arterial tissue through a pathway involving nitric oxide and a signaling molecule called cGMP. When researchers blocked nitric oxide production or stripped the inner lining of the artery in lab preparations, apigenin’s relaxing effect was significantly reduced, confirming that the compound works partly by prompting blood vessel walls to produce their own dilating signals. Apigenin also slowed the growth of smooth muscle cells in artery walls, a process that contributes to arterial stiffness over time.1General Pharmacology-the Vascular System. Endothelium-dependent vasorelaxant and antiproliferative effects of apigenin
A more recent study looked at the whole chamomile extract rather than isolated apigenin and found a dose-dependent effect on aortic tissue. At very low concentrations, the extract slightly increased contractility, but at higher concentrations it markedly reduced it, cutting contraction by roughly 90%. The extract also blocked contractions triggered through a receptor-mediated pathway, suggesting it interferes with calcium channels that blood vessel muscle cells use to tighten up.2PubMed Central. Cardiovascular effects of Matricaria chamomilla extract: calcium channel modulation and vasorelaxant activity
These are not trivial findings. Calcium channel blockers are one of the standard drug classes prescribed for high blood pressure, and here chamomile extract is mimicking at least part of that mechanism in a dish. The caveat is that concentrations achievable in a Petri dish or an organ bath are not necessarily the concentrations your blood vessels see after drinking a cup of tea. The jump from “relaxes a strip of aorta in a lab” to “lowers your systolic reading at the doctor’s office” is one of the biggest leaps in pharmacology, and chamomile has not yet made it in a controlled human blood pressure trial.
The Cholesterol and Blood Sugar Connection
Where chamomile tea has been tested in people, the outcomes measured are metabolic rather than blood pressure per se, but the two are closely intertwined. In a randomized trial of people with type 2 diabetes, drinking chamomile tea three times daily for eight weeks lowered total cholesterol, triglycerides, and LDL cholesterol compared to a control group.3Journal of Nutrition & Food Sciences. Effects Of Tea Consumption On Measures Of Cardiovascular Disease: A Systematic Review Of Meta-Analysis Studies And Randomised Controlled Trials A separate trial using a similar protocol found that chamomile tea significantly reduced HbA1c (a long-term blood sugar marker), fasting insulin, insulin resistance, total cholesterol, triglycerides, and LDL.4PubMed. Effectiveness of chamomile tea on glycemic control and serum lipid profile in patients with type 2 diabetes
These metabolic improvements matter for blood pressure because insulin resistance, high triglycerides, and elevated LDL all contribute to arterial stiffness and endothelial dysfunction, both of which drive blood pressure upward over time. Improving those markers does not guarantee a drop in blood pressure, but it removes some of the metabolic pressure that makes hypertension harder to control.
A third trial measured antioxidant enzymes alongside glycemic markers and found that chamomile tea boosted the activity of superoxide dismutase by about 26%, glutathione peroxidase by about 37%, and catalase by about 45% in the chamomile group compared to controls.5PubMed. Chamomile tea improves glycemic indices and antioxidants status in patients with type 2 diabetes mellitus Those enzymes neutralize reactive oxygen species that damage blood vessel walls, and their increase hints at a vascular-protective effect beyond simple cholesterol lowering. Still, all three of these trials involved people with type 2 diabetes, not people specifically recruited for hypertension, and none of them measured blood pressure as an outcome. The evidence is suggestive, not definitive.
Protecting the Inner Lining of Blood Vessels
High blood pressure both causes and is worsened by damage to the endothelium, the single-cell layer that lines every blood vessel. When that lining is healthy, it produces nitric oxide and other molecules that keep vessels flexible. When it is stressed by high glucose, inflammation, or oxidative damage, it loses that ability and blood pressure climbs.
Chamazulene, a compound found in chamomile essential oil, was shown to reduce reactive oxygen species in aortic endothelial cells exposed to high glucose concentrations and hydrogen peroxide. The researchers described this as the first evidence for chamazulene acting as a scavenging molecule in endothelial cells, suggesting it could help prevent the rise of oxidative stress that leads to vascular damage.6PubMed Central. Chamazulene Attenuates ROS Levels in Bovine Aortic Endothelial Cells Exposed to High Glucose Concentrations and Hydrogen Peroxide This is relevant for anyone with blood sugar issues, since high glucose is one of the main insults that damages the endothelium and accelerates hypertension.
Separately, chamomile tea has shown anti-inflammatory effects in animal models. In rats exposed to a chemical toxin, chamomile tea supplementation reduced markers of inflammation, oxidative damage, and cell death in lung tissue.7Beni-Suef University Journal of Basic and Applied Sciences. Chamomile tea as a supplement therapy relieves thinner induced-lung injury in rats through inhibiting inflammation, oxidative stress and P53-dependant apoptotic pathways The tissue was lung, not arterial, and the model was toxic exposure, not hypertension. But chronic systemic inflammation is a recognized contributor to elevated blood pressure, and the fact that chamomile dampens it across different organ systems is at least consistent with a cardiovascular benefit.
Stress, Cortisol, and Blood Pressure
One pathway that rarely gets discussed in the chamomile-blood pressure conversation is stress. Chronic psychological stress raises blood pressure through the sympathetic nervous system and through cortisol, a hormone that promotes sodium retention and vessel constriction. If chamomile can meaningfully reduce anxiety and normalize cortisol patterns, there is a plausible indirect route to lower blood pressure.
A study of people with moderate to severe generalized anxiety disorder found that those who experienced greater symptom improvement during chamomile extract therapy also showed significant changes in their daily cortisol patterns: morning cortisol increased while the overall cortisol output through the rest of the day dropped, producing a healthier, steeper cortisol curve.8PubMed Central. An Exploratory Study of Salivary Cortisol Changes During Chamomile Extract Therapy of Moderate to Severe Generalized Anxiety Disorder A flat cortisol curve, where levels stay elevated throughout the day, is associated with higher blood pressure and greater cardiovascular risk. Restoring a normal rhythm could chip away at stress-driven hypertension, though the study used a standardized chamomile extract at therapeutic doses, not ordinary tea. Whether a nightly cup produces the same cortisol normalization is unknown.
For people whose blood pressure spikes are partly driven by anxiety or poor sleep, chamomile’s calming properties could be doing more cardiovascular good than any direct vascular effect. That is speculation based on overlapping evidence rather than a tested hypothesis, but it is worth considering for anyone whose hypertension coexists with chronic stress.
Not All Chamomile Tea Is Created Equal
A practical problem undermines much of the optimism around chamomile tea: the actual bioactive content varies wildly between products. A study analyzing commercial chamomile tea bags found that total flavonoid content ranged from 0.17% to 0.55%, and levels of apigenin-7-glucoside, one of the key flavonoids, often did not meet pharmacopoeial standards.9PubMed. Chemometrically-supported quality assessment of chamomile tea That means the tea bag you buy at a supermarket might deliver a fraction of the flavonoids present in the chamomile used in research trials. There is no way to tell from the packaging.
Phytochemical profiling of chamomile flower extracts confirms a rich profile of phenolic and flavonoid compounds including gallic acid, chlorogenic acid, caffeic acid, apigenin-7-glucoside, quercetin derivatives, and kaempferol derivatives.10Letters in Organic Chemistry. Antioxidant Activities and Phenolic Profile of Chamomile (Matricaria recutita): A Herbal Tea from Pakistan The raw flower contains the goods. The question is how much survives processing, packaging, and your particular brewing method.
On that last point, research on extraction conditions found that chamomile steeped at about 90°C (just below a full rolling boil) for 20 minutes yielded the highest total phenol concentration while keeping the liquid clear. Lower temperatures extracted fewer bioactive compounds, while a full boil at 100°C increased turbidity without proportionally boosting phenol content.11Food Chemistry. Optimisation of the extraction and processing conditions of chamomile (Matricaria chamomilla L.) for incorporation into a beverage Most people steep their chamomile for three to five minutes, which almost certainly leaves a lot of the flavonoids still trapped in the plant material. If you are drinking it with any expectation of a health benefit, a longer steep with water just off the boil will get more of the active compounds into your cup.
Safety Concerns Worth Knowing About
Chamomile is generally well tolerated, but two safety issues deserve attention, especially for people managing high blood pressure who are likely on other medications.
The first is a potential interaction with warfarin and possibly other blood thinners. A case report described a 70-year-old woman on warfarin who was hospitalized with multiple internal hemorrhages after using chamomile products, including tea and body lotion, to soothe respiratory symptoms. Chamomile contains coumarin constituents that could theoretically potentiate the anticoagulant effect.12PubMed Central. Warfarin interaction with Matricaria chamomilla A single case report does not prove causation, but the plausibility is high enough that anyone on anticoagulants should mention chamomile use to their physician. Many people with hypertension also take blood thinners for atrial fibrillation or after a cardiovascular event, so the overlap is common.
The second concern is allergic reactions. Chamomile belongs to the Asteraceae family, alongside ragweed, mugwort, and chrysanthemums. A documented case of anaphylaxis after chamomile tea ingestion found cross-reactivity between chamomile tea extract and the pollens of giant ragweed and mugwort, mediated by IgE antibodies.13PubMed. Anaphylactic reaction after the ingestion of chamomile tea: a study of cross-reactivity with other composite pollens If you have a known allergy to ragweed or mugwort, your risk of reacting to chamomile is elevated. Most people will never have a problem, but a first cup is worth paying attention to if you have a history of pollen allergies.
Why the Human Trial Gap Matters
The pattern across all of this research is frustratingly consistent: promising mechanism, plausible pathway, no direct proof in the population that matters most. The vasorelaxation studies use isolated tissue. The metabolic trials enroll people with diabetes, not hypertension, and do not measure blood pressure. The antioxidant work is done in cell cultures. The stress research uses concentrated extracts, not tea.
This is not unusual for herbal interventions. Running a well-designed blood pressure trial is expensive and logistically demanding. You need to recruit enough people with confirmed hypertension, standardize the chamomile dose (which is hard given the variability in commercial products), run the trial for long enough to see a meaningful change, and control for all the lifestyle factors that influence blood pressure. Pharmaceutical companies fund these trials for drugs because they can patent the result. Nobody holds a patent on chamomile, so the financial incentive to run the definitive trial is weak.
What this means for you practically is that chamomile tea is not a substitute for blood pressure medication if you have been diagnosed with hypertension. The evidence base simply is not there to support that. It might, however, be a reasonable addition to a broader lifestyle strategy: something you drink in the evening instead of alcohol (which raises blood pressure), a ritual that helps you wind down before sleep (poor sleep elevates blood pressure), and a source of flavonoids and antioxidants that may offer modest vascular protection over time. Those indirect benefits are real even if the direct antihypertensive effect has not been clinically demonstrated.
How Chamomile Compares to Teas With Stronger Blood Pressure Evidence
It is worth placing chamomile in context. Green tea and hibiscus tea both have more extensive clinical trial data supporting modest blood pressure reductions in humans. Hibiscus in particular has been tested in several randomized controlled trials specifically designed to measure blood pressure as a primary outcome, and meta-analyses of those trials report small but consistent drops in systolic pressure. Green tea’s evidence comes partly from large observational studies of habitual tea drinkers and partly from intervention trials.
Chamomile has none of that direct trial evidence for blood pressure. What it has is a different mechanistic profile: strong anti-anxiety properties, anti-inflammatory effects, metabolic improvements in diabetic patients, and laboratory-confirmed vasorelaxation through calcium channel modulation and nitric oxide signaling. Whether those mechanisms translate into a clinically meaningful blood pressure reduction in a person drinking one to three cups a day is genuinely unknown. If blood pressure reduction is your primary goal and you are choosing a tea, the evidence currently favors hibiscus or green tea. If you are looking for a broader set of metabolic and stress-related benefits with a plausible but unproven cardiovascular upside, chamomile has more to offer than most people realize.
Pregnancy, Medications, and Other Special Situations
Pregnant women are sometimes advised to avoid chamomile tea or limit it to occasional use, because some animal studies have suggested uterine-stimulating effects at high doses. The clinical data in humans is thin, and moderate consumption appears to be safe for most pregnant women, but the caution persists in obstetric guidelines. If you are pregnant and managing gestational hypertension, talk to your provider before adding chamomile as a regular habit.
People taking sedatives, benzodiazepines, or other central nervous system depressants should be aware that chamomile has mild sedative properties that could add to drowsiness. For blood pressure specifically, there is a theoretical possibility that chamomile could enhance the effects of antihypertensive drugs if it does have genuine vasodilating activity in vivo, potentially causing blood pressure to drop too low. This is speculative and has not been reported in clinical practice, but it is the kind of interaction worth mentioning to your doctor if you are on multiple blood pressure medications and drinking large quantities of chamomile tea daily.
People with diabetes who are already on insulin or oral hypoglycemic agents should also be aware that chamomile tea lowered blood sugar and insulin resistance in the trials described earlier. Adding chamomile on top of existing glucose-lowering medication could theoretically increase the risk of hypoglycemia, especially if consumed in large amounts between meals. Monitoring blood sugar more closely when starting regular chamomile consumption is a reasonable precaution.