"Don't use ED medications -- Viagra, Cialis -- if you don't need them. Erections that last longer than four hours -- priapism -- can cause permanent scar tissue and permanent impotence. It's not a good idea to use these drugs casually."

If heart disease, stroke and certain cancers haven't been reason enough for men to quit smoking, consider this: The habit also increases the risk of erectile dysfunction. via KOLD-TV Tucson

Read more at: http://www.topix.com/health/erectile-dysfunction/2007/12/men-who-smoke-prone-to-impotence?fromrss=1.