Prostate Cancer

• The Mayo Clinic reports that some evidence suggests flaxseed may be associated with an increased risk of prostate cancer. Mayo notes, however, that research in regard to this possible connection is not yet conclusive.
  
  According to Mayo, a fatty acid in flaxseed known as alpha-linoleic acid, or ALA, may contribute to a higher incidence of prostate cancer. (ALA is the element that is responsible for reducing cholesterol in people who make regular use of flaxseed.)
  
  Because no definitive answer is available as to whether or not flaxseed increases the incidence of prostate cancer, Mayo recommends that men avoid using anything but a minimal amount of flaxseed to supplement their diets. Mayo advises men with prostate cancer to avoid flaxseed altogether.
  
  

Intestinal Blockage

• Intestinal blockage is another side effect of flaxseed. This type of blockage occurs when an individual consumes flaxseed without drinking any fluids. Consuming a small amount of flaxseed without drinking water or some other beverage will not result in blockage. However, a person ingesting anything beyond a small amount of flaxseed runs the risk of intestinal blockage if that individual does not drink water or some other beverage while eating flaxseed.
  
  

Impairment of Oral Medications

• Evidence suggests that the use of flaxseed is responsible for impairing the effectiveness of certain types of oral medications. The list of medications that can be affected is rather lengthy. For this reason, if a person who is prescribed a medication also takes flaxseed as a dietary supplement, it is essential that the doctor be alerted so she can decide whether or not flaxseed will impair the medication. If any doubts arise as to what effect flaxseed might have on a medication's effectiveness, the use of flaxseed should be stopped promptly.
  
  

Unsafe During Pregnancy

• The Mayo Clinic and other research centers have concluded that flaxseed should not be used by a pregnant woman. The use of flaxseed is demonstrated to hamper the proper growth of an unborn child. Additionally, instances of premature birth have been attributed to the use of flaxseed by a pregnant woman.
  
  

Severe Bleeding

• If an individual has any type of diagnosis of a disorder that results in the thinning of the blood or difficulty in controling bleeding, flaxseed should not be used. In these cases, the use of flaxseed can result in a further thinning of the blood.
  
  

Allergic Reactions

• As is the case with all other types of grains, some individuals actually are allergic to flaxseed. Consequently, if a person is considering incorporating flaxseed into her diet, it is advisable to begin by consuming only a small amount. This way, it is possible to gauge her body's response to flaxseed. Additionally, tests are available from allergists who can assist in determining whether or not an individual is allergic to flaxseed.