Could a headache be a sign of an allergic reaction to fish oil capsules?

[Julie]

Even though I was going to my chiropractor on a bi-monthly basis, I was still getting mild headaches on an almost daily basis for a little more than a month. Mind you I have been seeing him for a year and a half for regular adjustments and headaches were almost non existent since I started treatment. I complained that I had had these headaches for the last 4 or 5 weeks almost daily. He asked me if anything was new to my diet. I said I was taking fish oil capsules on a daily basis and also had a new/different prescription for my birth control pills. He suggested it was the birth control. Since I already had the pills and was ready to start the pack, I said I would give it one more month and see if anything changes. I did, however, stop taking the fish oil capsules and 48 hours later no more headache and none in the last 7 days since I stop taking them. Bye the way, I am not a seafood eater. I don't like the taste of ANY kind of seafood...fish or shellfish/crustaceans. Maybe I don't like the taste because it is my body's way of telling me I am allergic. The only other thing I can add about the fish oil capsules is that they contain lemon oil.