I just adopted a cat who was coming over a kitty cold, and after a couple days he has started throwing up, is this normal or should I be concerned?

Be very concerned

I agree with the others to take kitty to the vet. Some cats are sensitive to changes in diet so it could be as simple as transitioning from the food given at the Humane Society to the food at home.

Call or take to a vet. ...

The answer to this should be from your veterinarian. Cats can throw up for a number of reasons but your vet is best qualified to determine ehy.

I would definitely at least call the vet and see. Maybe call the humane society and see if their vet can see him since he had the cold when you adopted him.

Be concerned.......