Can Cannabis Users Donate Blood Red Cross 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 (or vaping) doesn't affect your ability to donate blood. Help us bust this myth by sharing our post.