Bromelain is a protein-digesting enzyme complex derived from the stem of the pineapple plant (Ananas comusus). Pineapple has been used medicinally by natives of the tropics for centuries as a digestive aid and wound healer. Current research is confirming its traditional use, finding that bromelain may have numerous health benefits, including anti-inflammatory, wound-healing, digestive, antidiarrheal, immunomodulatory, and anticancer effects. [1-4] Commercially, bromelain enzymes have been used for decades as a meat tenderizer and in cosmetic applications.
Bromelain is comprised of proteolytic enzymes or cysteine proteases, which hydrolyze proteins to oligopeptides and amino acids. They also exert proteolytic activity at cell surfaces, thereby altering receptor-ligand interactions. [1, 2, 5] Research suggests that bromelain may relieve inflammation by blocking the production of fibrin and kinin, inflammatory compounds which increase swelling and cause pain. [1, 2, 6] It is theorized that bromelain may also improve immunity by increasing production of interferon (a compound that inhibits the replication of viruses), Tumor Necrosis Factor (proteins that help destroy cancer cells), interleukin, and T- immune cells. [2, 3]
Pineapple plant Stem
Bromelain is used for its anti-inflammatory benefits for conditions such as arthritis, injuries, and surgical wounds. Studies suggest that bromelain supplementation may reduce the pain and inflammation associated with arthritis. [1-4, 7-9] Other studies show that bromelain may speed healing and reduce pain associated with injuries, burns, and surgical procedures. [1-4] Bromelain is reported to be effective in treating sports injuries (trauma) as well.  One study found a decrease in pain and swelling in 59 patients with musculoskeletal injuries when treated with bromelain. 
- Bromelain is used to support cardiovascular health by reducing risk factors for heart attack and/or stroke. Studies show that bromelain may inhibit platelet aggregation and possibly decrease the pain and inflammation associated with blood clots; improving some symptoms of angina and thrombophlebitis. [3, 11]
- Bromelain is used as a digestive aid for various digestive disorders such as diarrhea, stomach ulcers, gout, and pancreatic insufficiency. Experimental studies have shown that bromelain also possesses antidiarrheal effects and inhibits activity of the enterotoxins Escherichia coli and Vibrio cholerae. [1-4, 12, 13]
- Bromelain is also used in the treatment of upper respiratory tract infections (e.g. chronic bronchitis and acute sinusitis). Bromelain has been shown to have an antitussive effect (cough suppression) and mucolyic activity (reducing the thickness of mucus and bronchial secretions), making it effective in treating respiratory tract diseases. [1, 3] One study in particular demonstrated therapeutic effects in 87% of sinusitis patients treated with bromelain, compared with 68% of sinusitis patients treated with placebo. 
- Bromelain may provide anticancerous effects by inhibiting cancerous tumors. [14-16] A clinical study in mice found that bromelain decreased lung metastases of Lewis lung cancer cells.  Another study of 16 breast cancer patients also demonstrated the therapeutic effects of bromelain, when treated with an oral form. 
- Bromelain may have certain immune-enhancing effects and may boost the effectiveness of certain antibiotics. [17-22] Therapeutic effects in experimental allergic encephalomyelitis patients were noted when treated with bromelain, trypsin, and the flavonoid rutin, in study. 
- Bromelain may be helpful for women in the treatment of dysmenorrhea and breast engorgement during lactation. [2, 23] Researchers hypothesize that bromelain may have smooth-muscle relaxant effects on the uterus due to prostaglandin modulation. 
Dosage: Range from 500 - 2,000 GDU (Gelatin Digesting Units), taken 1-3 times daily. Apply bromelain topically as directed. [2, 24, 25]
Delivery Forms: Tablets, topical cream.
Bromelain should not be taken by individuals allergic to pineapples, honeybee stings, or olive pollen. Pregnant, lactating women and children should not take supplemental bromelain, unless recommended by a health care provider.
Side effects may include gastrointestinal symptoms, such as nausea, vomiting, diarrhea, and cramping, as well as metrorrhagia and menorrhagia.
Bromelain may enhance activity of some drugs such as anticoagulants (warfarin), antithrombotic agents (aspirin), and antibiotics (amoxicillin, tetracycline). Individuals taking these drugs should exercise caution in the use of bromelain. Bromelain may also have blood-thinning effects.
Always inform your health care provider about the dietary supplements you are taking, as there may be a potential for side effects and/or allergy. [1, 2, 25]
1. Pizzorno JE and Murray MT, eds. Encyclopedia of Natural Medicine, revised 2nd edition, CA: Prima Publishing, 1998: 784, 798.
2. Bromelain, PDR Health: http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml
3. Maurer HR. Bromelain: biochemistry, pharmacology and medical use. Cell Mol Life Sci. 2001 Aug;58(9):1234-45.
4. Taussig SJ, Batkin S. Bromelain, the enzyme complex of pineapple (Ananas comosus) and its clinical application. J Ethnopharmcol. 1988; 22:191-203.
5. Rowan AD, Butte DJ, Barrett AJ. The cysteine proteinases of the pineapple plant. Biochem J. 1990; 266:869-875.
6. Mynott TL, Ladhams A, Scarmato P, Engwerda CR. Bromelain from pineapple stems, proteolytically blocks activation of extracellular regulated kinase-2 in T cells. J Immunol. 1999; 163:2568-2575.
7. Klein G, et al. Reducing pain by oral enzyme therapy in rheumatic diseases. Wien Med Wochenschr. 1999;149(21-22):577-80.
8. Rovenska E, et al. Enzyme and combination therapy with cyclosporin A in the rat developing adjuvant arthritis. Int J Tissue React. 1999;21(4):105-11.
9. Rovenska E, Svik K, Stancikova M, Rovensky J. Inhibitory effect of enzyme therapy and combination therapy with cyclosporin A on collagen-induced arthritis. Clin Exp Rheumatol. May2001;19(3):303-9.
10. Masson M. [Bromelain in blunt injuries of the locomotor system. A study of observed applications in general practice]. [Article in German]. Fortschr Med. 1995; 113:303-306.
11. Metzig C, et al. Bromelain proteases reduce human platelet aggregation in vitro, adhesion to bovine endothelial cells and thrombus formation in rat vessels. In Vivo. Jan1999;13(1):7-12.
12. Chandler DS, Mynott TL. Bromelain protects piglets from diarrhea caused by oral challenge with K88 positive enterotoxigenic Escherichia coli. Gut. 1998; 43:196-202.
13. Mynott TL, Guandalini S, Raimondi F, Fasano A. Bromelain prevents secretion caused by Vibrio cholerae and Escherichia coli enterotoxins in rabbit ileum in vitro. Gastroenterology. 1997; 113:175-184.
14. Taussig SJ, Szekerczes J, Batkin S. Inhibition of tumor growth in vitro by bromelain, an extract of the pineapple plant (Ananas comosus). Planta Med. 1985;6:538-539.
15. Batkin S, Taussig SJ, Szekerezes J. Antimetastatic effect of bromelain with or without its proteolytic and anticoagulant activity. J Cancer Res Clin Oncol. 1988; 114:507-508.
16. Eckert K, Grabowska E, Strange R, et al. Effects of oral bromelain administration on the impaired immunocytotoxicity of mononuclear cells from mammary tumor patients. Oncol Rep. 1999; 6:1191-1199.
17. Desser L, Rehberger A, Paukovits W. Proteolytic enzymes and amylase induce cytokine production in human peripheral blood mononuclear cells in vitro. Cancer Biother. 1994;9:253-263.
18. Desser L, et al. Cytokine synthesis in human peripheral blood mononuclear cells after oral administration of polyenzyme preparations. Oncology. Nov1993;50(6):403-7.
19. Engwerda CR, Andrew D, Ladhams A, Mynott TL. Bromelain modulates T cell and B cell immune responses in vitro and in vivo. Cell Immunol. May2001;210(1):66-75.
20. Engwerda CR, Andrew D, Murphy M, Mynott TL. Bromelain activates murine macrophages and natural killer cells in vitro. Cell Immunol. May2001;210(1):5-10.
21. Brakebusch M, Wintergerst U, Petropoulou T, Notheis G, Husfeld L, Belohradsky BH, et al. Bromelain is an Accelerator of Phagocytosis, Respiratory Burst and Killing of Candida albicans by Human Granulocytes and Monocytes. Eur J Med Res. May2001;6(5):193-200.
22. Targoni OS, Tary-Lehmann M, Lehmann PV. Prevention of murine EAE by oral hydrolytic enzyme treatment. J Autoimmun. 1999; 12:191-198.
23. Snowden HM, Renfrew MJ, Woolridge MW. Treatments for breast engorgement during lactation (Cochrane Review). Cochrane Database Syst Rev. 2001;2:CD000046.
24. Bromelain, Dietary Supplement Information Bureau: http://content.nhiondemand.com/dse/consumer/monoAll-style.asp?objID=100182&ctype=ds&mtyp=1
25. Bromelain Tablets, Life Extension Foundation: http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml