Chamomile has a mild diuretic effect, but it’s significantly weaker than caffeine and unlikely to cause noticeable changes in urination at the amounts most people drink. In animal studies, chamomile roughly doubled urine output compared to a control group, but this was at concentrated doses consumed daily for three weeks. A cup or two of chamomile tea before bed won’t send you running to the bathroom any more than drinking the same amount of plain water would.
What the Research Actually Shows
The best direct evidence comes from an animal study at Hawler Medical University that measured urine output in rats given a concentrated chamomile decoction daily for 21 days. In healthy rats, chamomile more than doubled urine flow rate (from 0.014 to 0.035 ml/min/kg) and nearly quadrupled sodium excretion. Both results were statistically significant. The researchers also found a large increase in the kidney’s filtration rate, suggesting chamomile was genuinely affecting how the kidneys process fluid, not just adding water volume.
Interestingly, the effect was much weaker in rats with high blood pressure. Their urine output barely changed with chamomile treatment. The researchers concluded that chamomile has “mild diuretic activity” and that its effects resemble those of potassium-sparing diuretics, a class that increases water and sodium excretion without flushing out potassium. That’s a gentler profile than most pharmaceutical diuretics.
It’s worth noting these were concentrated doses given by oral syringe, not the equivalent of sipping a cup of tea. No human clinical trials have specifically measured chamomile’s diuretic effect, so extrapolating from rat studies to your evening mug requires caution.
Why Chamomile Has This Effect
Chamomile contains flavonoids, particularly apigenin and luteolin, that influence kidney function in several ways. Apigenin has been shown to reduce oxidative stress in kidney tissue, protect against inflammation, and limit fibrosis (scarring) in animal models of kidney disease. Luteolin similarly helps reduce kidney inflammation by calming immune signaling pathways.
More relevant to diuresis, flavonoids as a class appear to promote both water and sodium excretion through the kidneys. Research on related plant flavonoids has found diuretic and sodium-flushing effects tied to prostaglandin production, which affects how the kidneys regulate fluid balance. Several of these compounds also show potassium-sparing properties, meaning they help the body hold onto potassium even as it excretes more water and sodium. This aligns with the chamomile-specific findings from the rat study.
How It Compares to Caffeinated Tea
If you’re choosing between chamomile and black or green tea and wondering which will make you urinate more, caffeine is the stronger diuretic by far. Black, green, white, and oolong teas contain roughly 16 to 19 mg of caffeine per gram of tea leaves, and caffeine directly increases blood flow to the kidneys, prompting them to flush out more water.
That said, even caffeine’s diuretic effect is overstated at normal intake levels. You’d need more than 500 mg of caffeine (the equivalent of 6 to 13 cups of tea) to see a meaningful increase in urine production. Studies comparing black tea to plain water found no difference in urine output or hydration levels when people drank 4 to 6 cups over 12 hours. At moderate amounts, caffeinated tea is about as hydrating as water.
Chamomile tea is caffeine-free, so it lacks that particular mechanism entirely. Any diuretic effect comes from its flavonoid content, which is subtler. For practical purposes, drinking chamomile tea hydrates you much the same way water does.
What This Means for Daily Drinking
If you’re drinking chamomile tea for sleep, digestion, or relaxation, you don’t need to worry about dehydration or excessive urination. The general recommendation is 2 to 3 cups per day (200 to 250 ml each), prepared by steeping about a teaspoon of dried chamomile in hot water for 10 to 15 minutes. At this level, chamomile is considered safe for most adults and doesn’t cause significant side effects.
People with kidney or liver disease should be more cautious, as should pregnant or breastfeeding women. If you’re taking prescription diuretics or blood pressure medication, the mild additive effect of chamomile on sodium and fluid balance is at least worth mentioning to your doctor, even though it’s unlikely to cause problems at normal tea-drinking amounts.
The bottom line is straightforward: chamomile has real but mild diuretic properties in lab settings, and those properties are largely irrelevant at the concentrations you’d get from a few cups of tea. You’re adding fluid faster than chamomile could possibly flush it out.