"Emergency! You are being chased by an alligator."

Don't run!  Alligators are able to out run humans, and they can also climb trees. 

If the animal has not reached you, and you have something to move, throw, or run behind, your best bet is often to confuse him.  In this example, the writer used a lawn chair to discourage the animal…

David Claerr published this article "What it Feels like to Escape an Alligator Attack When Alligators Attack, There's No Looking Back, Jack" in which he describes: "My first impression was that I was looking at a huge turtle or tortoise. As my eyes focused , I suddenly realized that I was seeing an immense alligator that was heading directly for me! From head-on he was nearly round in cross section, like a barrel, and had a large, tumerous growth on his snout that obscured his appearance. He took a few slow-motion steps toward me, the deep mud sucking as he pulled up his feet. Then he made a sudden rush for me.  The realization of what he was up to hit me like a thunderbolt. Instinctive primal reflexes took over my body. In a flash, with no thought or volition, I went from flat on by back through a full flip backwards over the lawn chair, landing on my feet. I gripped the flimsy lawn chair in both hands, banged it around and screamed at the top of my lungs. The alligator stopped his rush at the other end of the lawnchair, bumping into it with his misshapen snout. I then spun around and bolted for the back door, nearly colliding with the people running out to see what was wrong.  I think the alligator only stopped because he didn't quite see where I had jumped to, and was just pausing to calculate his next move. Alligators can sprint at an amazing speed, and what probably saved me was the thick mud and steep embankment."

If you can't distract them, new articles report people punching them on the nose and escaping, running in a zig-zag, changing directions frequently.  There's info on the internet about wrestling them, but that should only be tried as a last resort, as gators are extremely strong.  If you find yourself in a physical confrontation with all those teeth, you really need to put downward pressure on the mouth, so he can't open it on you, and go for the eyes and nose.   

But the best tip comes from the Discovery channel, and it is actually to poke your thumb in the most sensitive part of the alligator.  A teen used this technique, poking the alligator in the eye with his thumb, and the gator found it so distracting that he let the youth go.  The story was reported in the in Deland, FL on July 23, 2006. 

Finally, see this worst-case scenario info on both AVOIDING (which is the best defense) such situations and also some guidance on what to do should the worst occur:

from http://www.geocities.com/hipnotiksgurl/:

 1. If you are on land, try to get on the alligator’s back and put downward pressure on its neck. This will force its head and jaws down.

2. Cover the alligator’s eyes. This will usually make it more sedate.
3. If you are attacked, go for the eyes and nose. Use any weapon you have, or your fist.
4. If its jaws are closed on something you want to remove (for example, a limb), tap or punch it on the snout. Alligators often open their mouths when tapped lightly. They may drop whatever it is they have taken hold of, and back off.
5. If the alligator gets you in its jaws, you must prevent it from shaking you or rolling over—these instinctual actions cause severe tissue damage. Try to keep the mouth clamped shut so the alligator does not begin shaking.
6. Seek medical attention immediately, even for a small cut or bruise, to treat infection. Alligators have a huge number of pathogens in their mouths.

How to Avoid an Attack
While deaths in the United States from alligator attacks are rare, there are thousands of attacks and hundreds of fatalities from Nile crocodiles in Africa and Indopacific crocodiles in Asia and Australia. A few tips to keep in mind:
1. Do not swim or wade in areas alligators are known to inhabit (in Florida, this can be anywhere).
2. Do not swim or wade alone, and always check out the area before venturing in.
3. Never feed alligators.
4. Do not dangle arms and legs from boats, and avoid throwing unused bait or fish from a boat or dock.
5. Do not harass, try to touch, or capture any alligator.
6. Leave babies and eggs alone. Any adult alligator will respond to a distress call from any youngster. Mother alligators guarding nests and babies will defend them.
7. In most cases the attacking alligators had been fed by humans prior to the attack. This is an important link—feeding alligators seems to cause them to lose their fear and make them more aggressive. 

You are in serious trouble if you are in the water, even if you can walk.  No help here.

Run is a good idea, but don't go charging into the water or high grass or brush.  You don't know what other critters are hiding out in there.  If you can run, I mean run, the alligator will not catch you.  A 'gator up close poses a real danger with there use of the tail.  You get whacked with a 'gator tail & you aren't going anywhere.  Aligators can kind of jump using their tail to push off.

Alligators can't climb trees, so the 'gator won't get at you, however, you may not be safe.  Snakes have been known to sleep or hunt for prey in trees.

Don't go charging blindly in 'gator country, on the ground or in a tree, they don't have a monopoly on getting you.