Btw my wife is a nurse with in a retirement facility. Many of her residents/patients are on Coumadin (Warfarin). All the ones taking fish oil have to have their coumadin adjusted(lowered). Anything which thins the blood can cause easy bruising. Here: [link to www.google.com] Corticosteroid medication and some dietary supplements (ginkgo and FISH OIL) are leading causes of easy bruising in many patients. Such formulations cause thinning of skin as one of its adverse effects, thus increasing the risk for bruising.People who are currently on blood thinning medication may experience easy bruising on legs. The ingested drug disturbs the normal blood clotting process, thus increasing the risk for bleeding and bruising incidences.