Although bromelain is generally considered safer than many synthetic medications, some side effects have been reported. Among these are nausea, vomiting, stomach pains, diarrhea, increased heart rate, breathing difficulties and profuse menstrual bleeding [source: Medline Plus].
Because bromelain affects blood viscosity and clotting, people who take anticoagulants or blood-thinning medications like aspirin or Coumadin should use extreme caution [source: Ehrlich]. Those taking herbal supplements that affect the blood, such as ginkgo biloba and saw palmetto, must also be careful [source: Medline Plus]. Those with a history of bleeding disorders, peptic ulcers, high blood pressure or a history of liver or kidney disease should consult a doctor before taking it [source: American Cancer Society].
Some studies suggest that bromelain may heighten the effect of sedatives like barbiturates, muscle relaxants like Valium and Xanax, anticonvulsants like Dilantin, sleep medications like Ambien, certain antidepressants and alcohol [source: Ehrlich].One study found that bromelain increased the body's uptake of amoxicillin. Therefore it is not advised to take it while on antibiotics.
Anyone who is allergic to pineapples should also avoid bromelain, as well as those with allergies to wheat, rye, carrots, celery, bee venom, papaya and certain pollens that the supplement may trigger [source: Ehrlich].
Like any medication, you should consult your doctor before taking bromelain to make sure it's safe and to find out what dosage is appropriate. Doses vary considerably depending on the nature and severity of your condition. It's generally not advised to take bromelain longer than eight to 10 consecutive days and it has not been recommended for use by children, pregnant women or nursing mothers [source: Ehrlich]. But it is recommended for certain men. Read on to find out whom.