Fish Oil & Bruising

Fish oil capsules in a wooden spoon.
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Fish oil is used to prevent and treat a variety of diverse conditions, such as depression, thinking disorders, glaucoma, diabetes, asthma, dyslexia and, most commonly, high blood pressure and heart disease. Though fish oil can provide significant benefits to the body, it has been known to also increase the risk of bruising.

Sources of Fish Oil

Fish rich in omega-3 fatty acids are mackerel, herring, tuna, mullet, salmon, trout, anchovies and sardines. A 3.5-oz. serving of fish provides approximately 1 g of omega-3 fatty acids. If you are not a fan of fish, supplements are another reliable way to get your daily dose omega-3 fatty acids. The dosage your body needs depends on the reason you are taking fish oil. Specific dosages are listed on the National Institutes of Health MedlinePlus website.

Blood Thinning Effect

Fish oil is a powerful tool to prevent coronary artery disease because it acts as a natural blood thinner. It inhibits the blood's ability to clot and reduces artery-clogging triglycerides, blood pressure and the risk of heart attack and stroke. Unfortunately, along with the fish oil's benefits comes unwanted side effects.

Risk of Bruising

Since fish oil is a natural blood thinner, it reduces your blood's ability to clot, and therefore, bleeding caused from capillary damage takes longer than normal to stop. As a result, when veins and capillaries break, blood leaks out of the vessels, pools under the skin and creates a bruise. Fish oil's ability to prevent blood clotting leads to the risk of prolonged bleeding and bruising, especially when consumed in combination with other blood thinning agents.

Interactions With Blood Thinners

The National Institutes of Health advises using caution when consuming fish oil in combination with blood thinning medications. Drugs prescribed to prevent blood clotting include aspirin, Coumadin, Fragmin, Lovenox, Persantine and Plavix. Some herbs and supplements, such as clove, danshen, garlic, ginger and ginkgo, are also known to slow blood clotting and should be taken with precaution if taken in combination with fish oil.


Bruising should not be taken lightly. If fish oil causes you to be prone to bruising, visit your doctor immediately. Excessive bleeding and bruising under the skin may cause various health hazards and should not be ignored. Your doctor will be able to suggest the appropriate steps necessary to treat and prevent further bruising.