Most people have already heard all the hype about how great fish oil is, but how many people have asked themselves: is fish oil harmful? It seems like a counterintuitive question to ask––after all, if these were bad for anybody, you would have heard about it by now… right?

Well, although it is healthy and beneficial for most people, there are definitely some instances (and certain individuals) where it’s not only not helpful, but potentially deadly. This is not to say that all the people out there taking this oil are being harmed, but do you remember the expression about how too much of a good thing is no longer good? This applies to fish oil too.

The most dangerous aspect of fish is the potential for poisoning from mercury or other lethal toxins. Unfortunately, there is a lot of pollution and junk in our oceans and rivers, so there are a lot of fish full of contaminants and toxins. All that stuff that gets into the waters is absorbed by the fish, and then when people eat the fish or harvest these oils and consume them, those people also accumulate toxins in their bodies. You do want and need the Omega-3 Essential Fatty Acids, but you do not want toxins, heavy metals, or contaminants of any sort.

Fortunately, for this problem, there is something called pharmaceutical-grade fish oil. The process for getting this is distillation, where the oil is stripped of all those toxins and contaminants, leaving just the Omega-3 Essential Fatty Acids. However, not all this oil on the market is pharmaceutical-grade. It’s up to you to do your homework and make sure you’re getting the right kind. Otherwise, you might be doing yourself more harm than good––and you could be doing yourself harm for a lot cheaper without it.

The other chief risk of this oil is when it’s combined with another blood thinner. Fish oil is an anti-coagulant (or blood thinner), which means that it stops you from having blood clots form. This is great if you’re trying to prevent a heart attack or reduce the damage of one that you’re having. It’s not great if you need to have a blood clot after you’ve injured yourself, because then you’re in danger of bleeding out. Taking this oil with aspirins, for example, is dangerous.

So, is fish oil harmful? Aside from some people who might be allergic or less able to digest it, pharmaceutical-grade oil is a healthy supplement. However, if you get just any generic brand, you run the risk of consuming toxins and contaminants in addition to the good stuff. Having toxins in your body is another source of chronic inflammation, which is one of the leading causes of a number of chronic or lifestyle diseases. If you are suffering from toxins in your body, you’re actually increasing the likelihood of these diseases than if you didn’t take anything at all.

For that reason, make sure that if you decide to take fish oil, you get the pharmaceutical-grade variety, and be careful about when you take it. It might be a good idea to consult a doctor to make sure that you’re not allergic and that you can handle it.