Actually, I think this only works with 8 pills, one of which is poisoned.

Take any six pills, put three on each side. If one side of the six weighs more, you have narrowed it down to the three pills on that side.
1) If it's even, none are poison, so weigh the last two to find the poison one. 2) If one side weighs more then take any two from that side and see which is heavier. If they're equal, it's the one you left off.

(If there are 9 pills, your inital weighing might leave one heavy side with 4 pills. There is no way to find the outlier with only 1 more weighing.)

p.s. If anyone doesn't get it, I'll post again with more details.
dackst Reviewed by dackst on . May I suggest this riddle? If you can stand another riddle, hereis one I have always liked! You are condemmed to death, but are given a chance. You are given a very precise balance (the kind that has two balancing trays) and nine pills. Eight of the pills are poisoned, and only one is safe to take. All nine pills are exactly the same in colour, look, size and weight, except that the safe pill is a bit heavier than the rest. You are only allowed to use the balance twice, and then you will have to eat one pill. What Rating: 5