Bromelain

What it is

Bromelain is a group of protein-digesting enzymes extracted from the stem and fruit of the pineapple plant. It is classified as a cysteine protease. Orally it is sold as a dietary supplement; a topical bromelain drug is approved for removing dead tissue from severe burns.

What the research says

The evidence is limited. A 2023 meta-analysis found oral bromelain reduced pain slightly more than controls in moderate-quality studies, and it may help sinusitis, but it was not effective for cardiovascular disease. Individual trials in knee osteoarthritis and after wisdom-tooth surgery found no statistically significant benefit over placebo. Side effects are usually mild and digestive, but allergy (especially in people allergic to pineapple) and a possible added bleeding risk with blood thinners are reported.

Evidence grade: Limited evidence.

What goes wrong

Adverse events reported with oral bromelain in the meta-analysed trials included flatulence, nausea and headache; the review found no major health risks. (Source 1)

• Meta-analysis, Moderate certainty.
• Size: 39 articles meta-analysed.
• Who: Trial participants taking oral or topical bromelain.
• How long: Varied by trial.
• Result: Rates not pooled in the abstract.
• Funding: not stated.

Adverse events included flatulence, nausea, and headache.

A 2026 narrative critical review states bromelain may increase bleeding risk when taken with anticoagulant or antiplatelet drugs, while noting the human evidence for a clear anticoagulant effect is limited and inconsistent. (Source 2)

• Expert review, not systematic, Very low certainty.
• Size: Narrative critical review (not a systematic review); no pooled data.
• Who: Not applicable.
• How long: Not applicable.
• Result: No rates reported.
• Funding: not stated.

it may increase the risk of bleeding when used concomitantly with anticoagulant or antiplatelet agents such as aspirin, warfarin, heparin, or NSAIDs

Bromelain can cause IgE-mediated allergy; earlier case reports describe asthmatic reactions from occupational inhalation, though the source says no recent case reports suggest such a response, and a rare contact cheilitis case followed use of a bromelain mouthwash. (Source 3)

• Case report, Low certainty.
• Size: Individual case reports.
• Who: Pharmaceutical and other workers exposed by inhalation; one mouthwash user.
• How long: Not applicable.
• Result: No rates reported.
• Funding: not stated.

there are some earlier case reports of allergenic asthmatic reactions due to bromelain inhalation as part of occupational exposure, none of the recent case reports suggest such inhalational allergic response towards bromelain

What the evidence supports

Across pooled trials, oral bromelain reduced pain slightly but significantly more than control, and the review rated the studies moderate quality. (Source 1)

• Meta-analysis, Moderate certainty.
• Size: 9 studies in the pain meta-analysis (54 articles reviewed, 39 meta-analysed)
• Who: Mixed clinical populations in trials of oral bromelain.
• How long: Varied by trial.
• Result: Mean difference in pain score -0.27 (95% CI -0.45 to -0.08), I2 = 29%.
• Funding: not stated.

Pain reduction from oral bromelain was slightly but significantly better than controls

What the evidence does not support

In a small placebo-controlled pilot trial in moderate-to-severe knee osteoarthritis, bromelain 800 mg/day did not beat placebo on the primary outcome. (Source 4)

• Randomized trial, Low certainty.
• Size: 47 randomised, 31 completed (14 bromelain, 17 placebo)
• Who: Adults with moderate to severe knee osteoarthritis.
• How long: 12 weeks plus 4-week follow-up.
• Result: Total WOMAC: coefficient 11.16, p = 0.27, 95% CI -8.86 to 31.18; no difference on WOMAC subscales or SF36.
• Funding: not stated.

No statistically significant differences were observed between groups for the primary outcome

In a small double-blind trial after lower third-molar extraction, bromelain did not differ significantly from placebo for swelling, pain or mouth opening. (Source 5)

• Randomized trial, Low certainty.
• Size: 34 patients.
• Who: Adults having impacted lower third molars removed.
• How long: 7 days.
• Result: No statistically significant differences between groups; a non-significant trend toward less inflammation.
• Funding: independent (authors declared no conflict of interest)

Although there were no statistically significant differences between the treatment groups

Where the evidence is mixed

The same systematic review concluded bromelain may help sinusitis but was not effective for cardiovascular diseases. (Source 1)

• Systematic review, Moderate certainty.
• Size: 54 articles in the qualitative review.
• Who: Mixed clinical populations.
• How long: Varied by trial.
• Result: Qualitative summary; no pooled effect quoted for sinusitis.
• Funding: not stated.

Bromelain may be effective against sinusitis but was not effective for cardiovascular diseases.

NCCIH (US National Institutes of Health), updated November 2024, holds that there is not enough high-quality research to recommend oral bromelain for sinusitis. (Source 6)

• Official position, Certainty not rated.
• Size: Not applicable.
• Who: Not applicable.
• How long: Not applicable.
• Result: Not applicable.
• Funding: government.

There is not enough high-quality research to say whether oral bromelain should be recommended for sinusitis.

Where the research disagrees

Whether oral bromelain relieves pain and swelling

• Leelakanok et al. 2023 meta-analysis, systematic review and meta-analysis: Moderate-quality studies demonstrated the potential of oral bromelain in pain control (Source 1)
• Brien et al. 2006 knee osteoarthritis trial, pilot RCT, n=47: This study suggests that bromelain is not efficacious as an adjunctive treatment of moderate to severe OA (Source 4)

How much

• Reference intake: No RDA or Adequate Intake exists: bromelain is a plant enzyme, not an essential nutrient. (Source 2)
• Upper limit: No tolerable upper intake level has been set by any body we found. (Source 6)
• Studied: Knee osteoarthritis pilot trial: bromelain 800 mg/day for 12 weeks (Brien 2006). (Source 4)
• Studied: Third-molar surgery trial: 150 mg/day for 3 days then 100 mg/day on days 4 to 7 (de la Barrera-Nunez 2013). (Source 5)

A common belief, and what the research shows

The belief: Bromelain is destroyed in the gut so it cannot act in the body.

What the research shows: A 2026 review says it 'has been reported to exhibit measurable systemic absorption following oral administration, despite the partial inactivation of proteolytic enzymes in the gastrointestinal tract.' Absorption does not by itself show a clinical benefit.

Questions and answers

What is it?

Bromelain is a mix of protein-digesting enzymes taken from the stem and fruit of the pineapple plant. (Source 6)

What does it do in the body?

It breaks proteins into smaller pieces. Some of it is absorbed after swallowing, but its effects on pain and swelling in trials are small or not significant depending on the condition. (Source 2)

Is it good or bad for you?

This review rated the studies moderate quality and found a small pain benefit for oral bromelain and a wound-care benefit for topical bromelain, with no major health risks reported during treatment. Reported side effects and the allergy and bleeding concerns are set out separately in the findings. (Source 1)

How do you get more of it?

Trials gave bromelain as capsules or tablets; pineapple stem and fruit are the natural source. Nothing here is a recommendation. (Source 6)

If it is harmful, what reduces it?

Does not apply in the usual sense; it is not made by the body. Reported side effects are mild and digestive, and stopping the supplement ends exposure. (Source 6)

Why might someone be low in it or missing it?

Does not apply. Bromelain is not a nutrient or a body substance, so no one is deficient in it; the body makes its own protein-digesting enzymes. (Source 6)

Which whole foods contain it or feed it?

Pineapple, specifically its stem and fruit. (Source 6)

What happens if you do not have it?

Nothing is known to happen; bromelain is not essential. Evidence of benefit when taken is itself limited. (Source 6)

How can you test for it?

No clinical test measures bromelain status because it is not a body nutrient. Allergy to bromelain is IgE-mediated and can be investigated by allergy testing; we found no validated accuracy data for a bromelain-specific test. (Source 3)

We searched: WebSearch for bromelain allergy testing and case reports; Thermo Fisher allergen encyclopedia entry k202

References

1. Nutrition and Health 29(3). Efficacy and safety of bromelain: A systematic review and meta-analysis. 2023. DOI 10.1177/02601060231173732. Read the source
2. Frontiers in Nutrition. Potential health benefits of bromelain: a critical review of the current literature. 2026. DOI 10.3389/fnut.2026.1744666. Read the source
3. Thermo Fisher Scientific (ImmunoCAP allergen encyclopedia). k202 Ana c 2 (bromelain) - Allergen Encyclopedia. Read the source
4. QJM: An International Journal of Medicine 99(12):841. Bromelain as an adjunctive treatment for moderate-to-severe osteoarthritis of the knee: a randomized placebo-controlled pilot study. 2006. PMID 17121765, DOI 10.1093/qjmed/hcl118. Read the source
5. Medicina Oral, Patologia Oral y Cirugia Bucal 19(2):e157-e162. Prospective double-blind clinical trial evaluating the effectiveness of Bromelain in the third molar extraction postoperative period. 2014. PMID 24316697, DOI 10.4317/medoral.19105. Read the source
6. National Center for Complementary and Integrative Health (NIH). Bromelain: Usefulness and Safety. 2024. Read the source