The former chief drug advisor to the UK government, who was sacked from that post in 2009, has published a study that examines the harm to the individual and to society of various drugs.
Heroin, crack cocaine, and crystal meth are the most harmful to individual users but the widespread use (and abuse) of alcohol is what makes it the most harmful to society, followed by heroin and crack cocaine.
I think many people fail to recognize how harmful alcohol can be. It effects every organ in the body and can cause permanent brain damage.
The health issues associated with drinking far outweigh any health benefits. Alcohol can be fatal.