8 grams unless you've got a bleeding condition, in that case just 1. Generally thats 1 tablespoon of Flax, but I recommend Fish gel caps, it will say how much each cap contains and thats how much you take depending.
Well, 240/260 mg of dha/epa a day is the recommended dosage by the american heart assoc. However thats even if you have bleeding issues. If no blood problems then up to 6g is good.