Why does your lovebird throw up?

Alot of times when a bird regurgitates on you or "throws up", it is performing a bonding ritual that it does with its mate. When a human bonds with a pet bird, the bird believes you are a mated pair. however, this is nice in theory as it is nice to think your bird loves you, it is most important that a bird keeps it's food down so it is advisable to place the bird back on it's perch to stop this behaviour. You are the owner, not the mate of the bird. If this does not describe what the bird is doing however, you need to take him to a vet incase something is wrong.