what is the best sleeping pills?!

The one you did not take!
Sure, some may suggest a natural hormone like melatonin, but self medicating with this hormone is not advisable. It is better used under the supervision of a doctor. And no doctor will prescribe it for long term use.
Sleeping pills could be addictive. And dependency on these pills could lead to an overdose as you might need more of it over time, as your body develops a tolerance for it.
Having said that, your best long term option is to find out why you can't sleep. After all there was a time you could sleep like a baby.
If you are under stress, try some relaxation technique such as meditation, exercising, bio-feedback, tai-chi etc.
If your inability to sleep is related to diet, then you need to eat healthy, with emphasis on fruits and vegetables, and pure water instead of juices and soda.
If it is related to lifestyle, then you need to get rid of any bad habits such as smoking, excessive consumption of alcohol, excessive stimuli such as too much television and computer work- what some call electronic pollution. Turn all lights off when you go to bed. Melatonin, the sleep hormone is best produced in darkness.
Interact with friends. Go to a good movie, preferably a comedy-laugh, it is relaxing.
Let go of yesterday and stop worrying about tomorrow. The world is not yours to run. Without you, the world will still go on. So stop worrying!
And you'll sleep better.

http://www.nontoxiclivingchoices.com/hol…

Since you asked under "alternative medicine"; 5htp or melatonin.