In a natural form of cod liver oil, with natural vitamins, the A & D work synergistically and you'd have to take an awful lot for it to be dangerous. A maintenance dose for a child would be about 1/4 tsp per day, but in this case you could give up to 1/2 tsp for a while. I'm more inclined to think that the omega 3's can be overdosed on if too much is taken over a long period.

Green Pasture check regularly for contamination. Somebody else brought up the so-called scandal in another comment, which I will address in answer to that comment (so you won't see it come up in your replies)