Can You Donate Blood if You Use Cannabis? The Cannigma We all know smoking and vaping isn't great for your health. But it doesn't stop you from being a blood or plasma donor. Just make sure to wait one hour after donating We all know smoking and vaping isn't great for your health. But it doesn't stop you from being a blood or plasma donor. Just make sure to wait one hour after donating Smoking and vaping don't affect your eligibility to donate. Become a donor and give life today.