Can You Donate Plasma If You Smoke Weed? Get Facts Here! The Sanctuary Cannabis Use and Blood Donation: Unmasking the Truth Smoking (or vaping) doesn't affect your ability to donate blood. Help us bust this myth by sharing our post. Can Marijuana Use Prevent You From Giving Blood? 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