It's less harmful than cigarettes - nicotine is a vasoconstrictor and bronchioconstrictor. Weed is neither, and actually also has expectorant qualities, so you

It's less harmful than cigarettes - nicotine is a vasoconstrictor and bronchioconstrictor. Weed is neither, and actually also has expectorant qualities, so you tend to cough most of the tar back up. That said, smoking anything is not good for you, but IMHO it's up to the individual what risk they take with their body.