"I am legend" movie?

Question

At the end when that guy finds the cure against zombies and says "its not blood" and then it shows those butterfly s, does anyone have any theories about what the cure is?

Answer 1

I thought he said, "the cure is in her blood" then he gives the woman the vial with the zombie girls' blood in it, because she was starting to get normal again.

Answer 2

You know there is an alternate ending that makes more sense.

The guy gives the zombie's leader back his girlfriend and they leave.

Then he and the woman and the boy head to the surviver's colony.

Answer 3

The butterfly was a symbol on his daughter that you saw when he was loading her onto the helicopter.  The lady who came to inspire him to keep working on a cure and who ultimately took it back also had a tattoo of a butterfly.  It was a premonition or foreshadowing of what was to come and how the stranger was SUPPOSED to meet him to take the cure to the survivors.

The cure was an antidote to the original "cancer cure" that ran amok.

He had been treating with different serums and the last zombie lady improved.  He saw that when the zombie lover/boyfriend was attacking and knew that the zombie lady had the antibodies in her that were reversing the original problem.  He took blood to give to the lady with the boy and with the butterfly tattoo to take to the Survivors.

Answer 4

He found a vaccine which cured the zombie.

He drew some of the "cured" zombies blood and gave it to the woman.

While the blood wasn't actually the cure, it contained the cure which the scientists could later isolate and make more of.

Sorry...I don't remember butterflies...