• Fish oil can benefit the heart.Fish oil vitamins image by Stephen VanHorn from Fotolia.com
  
  Fish oil is praised for its many benefits. Packed with omega-3 fatty acids, the oil can be taken in capsule form as a supplement to a person's diet. These fatty acids are helpful for a number of conditions, ranging from heart disease to psychological disorders. However, there are some side effects to keep in mind when taking the capsules.
  
  

Heart Disease

• Fish oil may lower blood triglyceride levels, according to the University of Maryland Medical Center (UMM). High triglyceride levels may increase the chance of developing coronary artery disease. Some evidence suggests that fish oil prevents the hardening of arteries, according to the UMM. Fish oil also benefits those with a heart attack history. The oil may prevent another heart attack from occurring, says the U.S. National Library of Medicine.
  
  

Psychological Disorders

• The omega-3 fatty acids found in fish oil may help depression, especially postpartum depression, according to the U.S. National Library of Medicine. When treating depression, a combination of antidepressants and fish oil may be even more effective, according to Daniel K. Hall-Flavin, M.D., a psychiatrist with the Mayo Clinic. According to the UMM, fish oil may also lessen mood swings and lengthen time between main episodes in people with bipolar disorder.
  
  

Rheumatoid Arthritis

• For people with rheumatoid arthritis, fish oil not only relieves joint pain and tenderness but also reduces dependence on corticosteroid medications, according to the Office of Dietary Supplements, which is part of the National Institutes of Health. Fish oil may also assist non-steroidal anti-inflammatory drugs in pain treatment, according to the U.S. National Library of Medicine.
  
  

Stomach Side Effects

• Unfortunately, the benefits of fish oil come with some side effects. Some people may experience belching and bloating, says the UMM. Diarrhea is also another unpleasant side effect. Diarrhea may become severe if high doses of fish oil are taken. These side effects may be minimized if the supplement is taken with meals, according to the U.S. National Library of Medicine.
  
  

Bleeding Problems

• Fish oil may increase the chances of excessive bleeding. This is more likely to occur when taking large doses of fish oil, according to the U.S. National Library of Medicine. According to the UMM, people with blood-clotting disorders and those who bruise easily should be cautious when consuming fish oil.
  
  

Interactions

• Because fish oil may increase bleeding, people who take blood-thinning medications like aspirin or warfarin should avoid fish oil, according to the UMM. Fish oil may also decrease blood sugar slightly. Precautions should be taken if a person takes medications like insulin that also lower blood sugar, according to the U.S. National Library of Medicine.