The actor is still recovering from surgery last year for nerve-related issues.
A source told Mid Day: "Salman bhai is in his prime. He is enjoying success like never before and has become extremely disciplined.
"After his health scare around a year back due to trigeminal neuralgia, Salman does not want to hamper the recovery process any more. That's why he decided that he would quit smoking and drinking."
He went on: "Salman's illness scared everyone around him and his family. He now does not want to do anything that will upset his family members and quitting drinking and smoking is the first step towards that."
It was reported in March that the actor was on medication for jaw problems.
The star was forced to drop out of playing celebrity cricket in January, reportedly because of his health.