According to an article at nature.com, studies done by Charles Serhan and his team of researchers at Harvard suggest that you might want to take aspirin with your fish oil:

Their work in human cells and in mice showed that omega-3 fatty acids in the fish oil are converted into lipids that seem to suppress inflammation. Aspirin speeds up that conversion.

Serhan and his team also think they found the mechanism by which this happens, and created a synthetic form!

The researchers have now pinned down the effect even further by focusing on one of the lipids, called resolvin E1. First they found that healthy human volunteers fed both aspirin and fish oil had resolvin E1 in their bloodstream. Then they created a synthetic form of the lipid and tested its properties.

The results?

The lipid inhibited the migration of particular human immune cells and dramatically reduced inflammation on the skin of rabbits.

The article also states that Serhan is hoping to cheaply make his synthetic lipids in bulk and start testing on humans. Is this “resolvin E1″ behind the inflammatory effects of fish oil? According to Serhan, it’s just the “tip of the iceberg” and they plan to examine all the lipids found in fish oil. Are synthetic fish oils on the horizon? Perhaps in several years — but until then you’d better stick to a highly-purified pharmaceutical grade fish oil.