Celery seed: blood pressure trials used extracts, not the spice jar

A 2025 meta-analysis of 10 randomized trial arms in 511 adults found that celery preparations lowered systolic blood pressure by a standardized mean difference of 1.0 (95% CI 0.14 to 1.85). The adults had hypertension, prediabetes, polycystic ovary syndrome or overweight, mostly in Iran, and took extract capsules of 10.55 to 2,250 mg a day or decoctions for 12 to 84 days. The trials disagreed sharply with each other (I2 94%). The result is in standardized units, so it cannot be read as millimeters of mercury. Every trial gave the seed as an extract or a decoction, and we found no trial of whole seed at the amounts a recipe uses. These were doses studies used for at most 84 days, not a tested safe amount. We have no card that sets an upper limit for celery seed extract or covers its interactions with medicines. Its safety in pregnancy has not been established, since the trials did not include pregnant women. In one trial blood pressure fell on top of the usual drugs, so anyone taking medicine for blood pressure or blood sugar, or who is pregnant, should talk to a doctor before taking the extract.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• USDA lists celery seed at 44.9 mg iron, 1,767 mg calcium and 1.37 mg copper per 3.5 oz (100 g), far above most foods, though a spice serving is only a few grams. — USDA SR Legacy food Spices, celery seed (FDC 170920) (n = 1 record) Evidence E source
  Per 100 g: iron 44.9 mg, calcium 1,767 mg, copper 1.37 mg

What cooking and storage change

• In blinded food challenges in people allergic to celery, all 5 tested reacted to celery spice and 6 of 11 still reacted to celery cooked at 110 C for 15 minutes, so heat and drying do not remove the allergy risk. — 12 patients with a history of allergic reactions to raw or cooked celery, Germany (n = 12) Evidence C source
  Celery spice 5 of 5 positive; cooked celery 6 of 11 positive; some reacted after 76 min at 100 C

What it does to your health

• A 2025 meta-analysis of 10 randomized trial arms with 511 adults found celery preparations lowered systolic blood pressure (SMD -1.0) in adults with hypertension, prediabetes, PCOS or overweight. — adults with hypertension, prediabetes, PCOS or overweight in Iran, Indonesia and China; capsules 10.55-2,250 mg/day or decoctions for 12-84 days (n = 511) Evidence A source
  SBP SMD -1.0 (95% CI -1.85 to -0.14); DBP SMD -0.93 (-1.54 to -0.33); fasting glucose SMD -0.80 (-1.58 to -0.01)
• In a crossover RCT in 50 people with hypertension, 1.34 g a day of celery seed extract for 4 weeks cut Beck anxiety scores by 6.78 points and depression scores by 3.63 points. — 50 hypertensive patients in Iran on usual medication, 4-week periods with 4-week washout (n = 50) Evidence B source
  BAI -6.78 (P<0.001); BDI -3.63 (P<0.01); blood pressure also fell (P<0.001)

Safety, limits and interactions

• Across the celery trials in a 2025 meta-analysis, six reported safety data, and the review found no significant difference between celery and placebo in severe or mild adverse events. — adults in 9 randomized trials of celery capsules or decoctions, 12-84 days (n = 511) Evidence A source
  No significant difference in severe or mild adverse events vs placebo; 3 of 9 trials reported no safety data

What people believe that the data does not support

• The EU did not authorize the claim that celery supports normal bladder function. — EU Register on nutrition and health claims, snapshot 2026-09-21 Evidence E source
  Status non-authorized; 0 of 3 Apium graveolens claims authorized
• The EU also rejected the claim that celery helps the kidneys eliminate water, the basis of its reputation as a natural diuretic. — EU Register on nutrition and health claims, snapshot 2026-09-21 Evidence E source
  Status non-authorized

Who this works differently for

• Blinded challenges confirmed celery allergy in 22 of 32 people who reported reactions to celery, most of them pollen-sensitized. — 32 patients with a history of allergic reaction to celery root, Germany (n = 32) Evidence C source
  22 of 32 positive DBPCFC; 2 reacted to placebo; 8 no response

What is still unknown

• The UK table gives celery seeds 25.3 g fat, 18.1 g protein, 1,770 mg calcium and 44.9 mg iron per 3.5 oz (100 g), the same iron and nearly the same calcium as USDA, so the two tables are likely not independent measurements. — CoFID food Celery seeds (code 13-810) (n = 1 record) Evidence E source
  Per 100 g: fat 25.3 g, protein 18.1 g, calcium 1,770 mg, iron 44.9 mg, potassium 1,400 mg, sodium 160 mg

The bottom line

On paper the seed is dense in minerals. USDA lists 44.9 mg iron, 1,767 mg calcium and 1.37 mg copper per 3.5 oz (100 g), but a spice serving is a few grams, so these figures overstate what you eat. The UK table repeats the same iron value, which suggests borrowed numbers, and there is no second sample to show how much real seed varies. We found no study of how much of that iron or calcium the body absorbs. In a triple-blind crossover trial, 50 people in Iran with hypertension took 1.34 g a day of seed extract for 4 weeks on top of their usual drugs. Anxiety scores fell by 6.78 points and depression scores by 3.63, and blood pressure fell too. It was one center, short periods, and an extract standardized to 3-n-butylphthalide. Allergy is the real caution, and cooking does not remove it. In German blinded food challenges, all 5 celery-allergic patients tested reacted to celery spice, and 6 of 11 reacted to celery cooked at 110 C for 15 minutes. The study did not say whether the spice was seed or dried root. In a second German study, challenges confirmed allergy in 22 of 32 people who reported reacting to celery root, most of them sensitized to pollen. If you react to celery, treat the seed as celery. In the pooled trials, 6 of 9 reported safety data and showed no more severe or mild adverse events with celery than with placebo. Those trials were short and did not include pregnant women or allergy-prone people, and we found no agency text on celery seed in pregnancy, so the safety of extract doses in pregnancy is not established. The EU has not authorized the claims that celery supports bladder function or helps the kidneys eliminate water, the basis of its name as a natural diuretic. Non-authorized means the evidence fell short at assessment. In the US, supplements do not go through FDA approval the way medicines do, so anyone who takes medication, is pregnant or has a chronic illness should talk to a doctor before taking one.

Sources

1. clsd-r2-01 · food composition dataset
   Spices, celery seed, FDC 170920: Iron 44.9 MG, Calcium 1767 MG, Copper 1.37 MG per 100 g
   USDA SR Legacy 2018, Spices, celery seed, FDC 170920 · checked 2026-09-30
2. clsd-r2-06 · food challenge study
   Six out of 11 patients showed a positive DBPCFC to cooked celery and five out of five patients to celery spice. ... 2) Celery spice is allergenic for patients with an allergy to raw celery.
   Allergy, 2002 · checked 2026-09-30
3. clsd-r2-03 · meta-analysis of RCTs
   The results demonstrated significant therapeutic effects of celery on systolic blood pressure (SMD: -1.0; 95% CI: -1.85 to -0.14), diastolic blood pressure (SMD: -0.93; 95% CI: -1.54 to -0.33) ... Subgroup analysis revealed that celery seeds or celery preparations exceeding 1,000 mg/day were more effective than other parts of celery.
   Front Nutr, 2025 · checked 2026-09-30
4. clsd-r2-05 · RCT (crossover)
   Fifty hypertensive patients received 4 placebo or celery seed extract capsules (1.34 g per day) for 4 weeks as a supplement to their usual medication regimen. ... In the celery treatment step, the mean reduction in BAI and BDI scores were 6.78 (P < 0.001) and 3.63 (P < 0.01), respectively.
   Inflammopharmacology, 2023 · checked 2026-09-30
5. clsd-r2-04 · systematic review of RCTs
   Regarding safety outcomes, six trials reported adverse events or safety outcomes associated with celery or placebo, while three studies did not provide safety information (16, 50, 51). ... No significant differences were observed between celery and placebo in terms of severe adverse events, and there was no notable difference in mild adverse events between celery and control groups.
   Front Nutr, 2025 · checked 2026-09-30
6. clsd-r2-08 · regulatory decision
   POL-HC-6620 Apium graveolens Support of normal bladder function Non-authorised
   EU Register on nutrition and health claims, claim POL-HC-6620, snapshot 2026-09-21 · checked 2026-09-30
7. clsd-r2-09 · regulatory decision
   POL-HC-6622 Apium graveolens - common name : celery Used to enhance the renal elimination of water / "Used to facilitate the elimination functions of the organism" / "Used for the drainage of the organism" / "Stimulates the elimination function of the organism" / "Contributes to the functionary of the urinary tract" Non-authorised
   EU Register on nutrition and health claims, claim POL-HC-6622, snapshot 2026-09-21 · checked 2026-09-30
8. clsd-r2-07 · food challenge study
   Celery root is a frequent cause of food allergy in pollen-sensitized patients. ... Twenty-two of 32 patients had a positive DBPCFC result.
   J Allergy Clin Immunol, 2000 · checked 2026-09-30
9. clsd-r2-02 · food composition dataset
   Celery seeds, CoFID 13-810: Fat 25.3 g, Protein 18.1 g, Calcium 1770 mg, Iron 44.90 mg, Potassium 1400 mg, Sodium 160 mg per 100 g
   CoFID 2021, Public Health England, OGL v3.0, Celery seeds, code 13-810 · checked 2026-09-30