Here are three prevention ways from taking drugs:
Give your teen good reasons not to take drugs (this is the most effective action ! )
Many teens are tempted without knowing why. On the other hand, those who refuse always know why: because they have projects, that they care about their good health ...
Prevent your teen from being in risky situations
Going to deserted streets near their establishment, being away from home after 11 pm, going to unguarded teenage parties ...
Always show him the example
The behavior of parents (and not only in the face of drugs, alcohol as well), it matters a lot.