Well, its still hard to decide which is the most dangerous drug of all. All are as fatal as each other. But some of the examples are ecstasy, amphetamines, cocaine and heroin.

i have taken half an ecstacy before and the next day the whole side of my body went numb.... this was over 3 years ago now, but do you think iv damaged myself cause i feel pretty much dizzy all the time now since then, what do you think that is?

those types of drugs can have life long side affects. so can every drug really. I have never done ecstasy or know anyone who has. I would talk to a doctor if you are really concerned about it. The dizziness is enough to talk to someone about. It could be a reaction or be totally different.

As for the most dangerous, they are all dangerous. They are addictive and can lead to so many problems. You risk overdose with the stronger drugs like heroin and meth, where as pot cant kill you. but I have heard of people trying drugs for the 1st time and having serious reactions

All drugs are dangerous, many for sifferent reasons.
Anything that can completely cause a person to self destruct is dangerous.
Like Rosie said drugs like meth and herion etc. can cause overdoses but any drug used for a long period of time can have serious negative effects.