Why does clot keep falling out 2 days after wisdom teeth removal?

It depends: The clot may come out due to a variety of causes. There may have been too much suction (drinking through a straw), exposure to alcohol (many mouthwashes), smoking or development of a dry socket (infection of the bone). It is best to visit the surgeon and have it evaluated.

Blood clot out: You may be doing something you were instructed not to do that could be disrupting the clot formation and causing it to fall out. However if you are still bleeding enough that you are clotting, losing the clot, reclotting, losing the clot, reclotting then losing the clot you should have the surgeon look at the area to make sure it is beginning the healing process and if it needs sutures to help.