The dangers
Drug use can never be 100 per cent safe but it is not always as dangerous as many people think. The dangers of drug use depend on drug, set and setting factors.
The drug bit is everything connected with the drug and how it is used. The set bit is everything connected with the person who is using the drugs. The setting bit is about what the person is doing at the time, where they are, the environment they live in etc.
The basic principle is that drug dangers are the result of interactions between drug, set and setting.