Herb library · Spice · Apium graveolens
Celery seed
The small seed of the celery plant, a kitchen spice that is also sold in capsules for blood pressure. Small trials suggest celery preparations, especially the seed, may lower blood pressure a little, but the studies are few, small and inconsistent.
Traditional use
Celery, called smallage in old English herbals, was used in European medicine to make people pass more urine, to bring on periods and to expel wind. Celery turns up in spice blends and soups, and today celery seed extract is sold as a supplement, mostly for blood pressure, blood sugar and blood fats.
What studies show
- Limited
Blood pressure: a 2025 review of 10 small randomized trials (511 people) found celery preparations lowered systolic and diastolic blood pressure, with seed preparations above 1,000 mg a day doing best. The authors note large differences between studies and small sample sizes. In one 2022 trial of 52 people with high blood pressure, 1.34 g a day of seed extract for 4 weeks lowered average systolic pressure from about 141 to 130 mmHg.
- Limited
Blood sugar and blood fats: the same review found lower fasting blood sugar and triglycerides, but no overall effect on total, LDL or HDL cholesterol. The evidence has the same limits: small, varied studies.
Be careful of
Cautions
- AllergySome people are allergic to celery. In a 2018 study, celery-allergic patients reacted to celery root in blinded, placebo-controlled food challenges.
- InteractionIn the blood pressure trials, celery seed extract was taken on top of people's usual blood pressure medicines. If you take them, talk with your clinician before adding it.
- NoteCelery contains psoralens, which make skin more sensitive to ultraviolet light. One woman had a severe burn at a tanning salon an hour after eating a large amount of celery root.
- AmountA single case report describes an overactive thyroid in a man who took 4 g of dried celery leaves a day for 45 days to lose weight; it cleared after he stopped.
- NoteIn the trials reviewed, side effects were no more common than with placebo.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“Smallage seed, provokes urine and the menses, expels wind, resists poison, and eases inward pains, it opens stoppings in any part of the body, yet it is hurtful for such as have the falling-sickness, and for pregnant women.”
Sources
- Effects of celery (Apium graveolens) on blood pressure, glycemic and lipid profile in adults: a systematic review and meta-analysis of randomized controlled trials (Front Nutr, 2025) (opens in a new tab) · NIH · read September 25, 2026
- Effect of celery (Apium graveolens) seed extract on hypertension: a randomized, triple-blind, placebo-controlled, cross-over, clinical trial (Phytother Res, 2022) (opens in a new tab) · NIH · read September 25, 2026
- Clinical reactivity of celery cultivars in allergic patients: role of Api g 1 (Clin Exp Allergy, 2018) (opens in a new tab) · NIH · read September 25, 2026
- Severe phototoxic burn following celery ingestion (Arch Dermatol, 1990) (opens in a new tab) · NIH · read September 25, 2026
- Is herbal therapy safe in obesity? A case of Apium graveolens (celery) induced hyperthyroidism (ARYA Atheroscler, 2016) (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.