Alcohol is more harmful than marijuana.
For starters, while alcohol has negative health effects, not marijuana. Furthermore, no one has ever died from a marijuana overdose, and is considered to be impossible. On the other hand, alcohol favors the emergence of violent and aggressive behavior, while marijuana is relaxing. Dependence caused by alcohol is a psychological and physical, and becomes very strong. Marijuana causes some psychological addiction only, and cases of drug addiction in many cases are due to previous problems such as depression or anxiety.
In my case, I don't consume nor alcohol or marijuana, and I live happy.