Yes, they both do. Smoking causes damage to blood vessels and this slows blood flow to the penis. In one study it was found that male smokers with high blood pressure and/or other risk factors were more than twice as likely to have complete ED than those who didn't smoke. If you drink alcohol, it’s best to have no more than two drinks a day. Alcohol slows down your central nervous system and can make it more difficult for you to get an erection.