Fish oil contains omega-3's, it's very good for your heart! If any of you take fish oil and you end up burping it up and tasting it (so sick), then it's synthetic and your body does not recognize it because ANYTHING synthetic the body recognizes as a "poison", period. ALL vitamins you buy at GNC or ANY other vitamin store, they are ALL synthetic that's why if you are take them on an empty stomach and they give you a sick uneasy feeling in your stomach, they are NOT natural. That's crazy, huh? BELIEVE IT or NOT.