Is Blood Donation Allowed if You Consume Marijuana? What Arthritis and Chronic Pain Patients Need to Know About the Vaping Crisis Myth: You can't donate blood if you smoke or drink. Fact: Smoking or occasional drinking doesn't automatically disqualify you. But avoid alcohol for at least 24 hours before donating to Can Smoking Marijuana Increase Stroke Risk? Health Matters NYP Is Blood Donation Good for Health? Dr. Karuna Kumar