Can I Donate Blood If I Use Cannabis On A Regular Basis?

In our latest question and answer, our cannabis pharmacist discusses whether it's safe to donate blood if you use cannabis regularly.
Can I Donate Blood If I Use Cannabis On A Regular Basis?

Pat Asked

Can I still donate blood if I use cannabis regularly?


The legal or illegal use of cannabis does not disqualify an individual from donating blood.
However, donors should avoid using cannabis immediately before and after giving blood.
If your memory or comprehension skills are at all impaired from cannabis, alcohol, or any other drugs you cannot donate blood.


Hi Pat, thank you for this important and responsible question. According to the National Heart, Lung, and Blood Institute (NHLBI), almost 5 million Americans receive blood transfusions every year, for medical and other reasons.

The blood used for these critical procedures is collected via blood donations. Donating blood is a great way to help someone in need who requires a blood transfusion. Before you make a donation, you’ll be asked a series of important questions regarding your health, travel history, and lifestyle, to ascertain your eligibility. This is where responsible individuals (like yourself) who use cannabis become concerned. Many people know that chemicals present in cannabis, such as THC, linger in the system for quite some time.

Individuals that use cannabis and are seeking to donate blood may hesitate from doing so, assuming that they will test positive for THC and be considered ineligible. But is this actually true? The short answer is no. Cannabis use does not preclude you from donating blood. However, there are a few things to consider.

Cannabis and Blood Donations

Can I Donate Blood If I use Cannabis?

The American Red Cross regularly runs blood donation drives all across the United States. While they strictly discourage the use of illegal drugs, they state that using cannabis does not necessarily prevent an individual from donating blood.

“Legal or illegal use of marijuana is not otherwise a cause of deferral”

–American Red Cross

However, they also state that potential donors must not be under the influence of cannabis while donating blood. Clinics will consider you ineligible if you appear visibly impaired or under the influence of cannabis (high). Red Cross repeatedly emphasizes that potential donors cannot donate blood if using cannabis impairs their comprehension or memory. The decision to donate blood must be made by an individual that is free from the impairment of drugs and alcohol, including cannabis and other legal or illegal drugs.

Are Blood Donations Tested for THC or other Cannabinoids?

Despite going through various lab tests and procedures to confirm that donations are safe for use, cannabinoid testing is not routinely required for donated blood. Hence cannabis consumers should not be worried about this as a reason not to donate blood.

What About Synthetic Cannabinoids?

The American Red Cross states that they have certain concerns about synthetic cannabis since some varieties might contain anticoagulants that would contaminate plasma. For this reason, the ultimate decision about receiving blood donations from synthetic cannabis users depends on the individual blood donation center. Make sure you tell your donation center if you’ve been using synthetic cannabis just to be safe.

Can I use Cannabis After a Blood Donation?

It’s wise to avoid using cannabis shortly after giving blood. Cannabis may cause hypotension in some users and after a blood donation, the risk for hypotension may be increased depending on the volume of blood donated. Red Cross states the following on their website,

“The plasma from your donation is replaced within about 24 hours. Red cells need about four to six weeks for complete replacement. That’s why at least eight weeks are required between whole blood donations.”

–American Red Cross

Bottom Line

As long as you are in good health and aren’t suffering from any serious medical conditions, you qualify as a potential blood donor even if you use cannabis regularly. The one exception is if you use synthetic cannabis in which case the decision of whether to accept your donation will ultimately be up to the individual blood donation clinic.

Remember, even though blood donations are not tested for cannabinoids, blood banks will still require your complete and sober consent. If you try to donate blood just after smoking a joint and seem visibly under the influence, your memory or comprehension might be impaired and you will probably be asked to leave or come back another time.

If you cannot avoid using cannabis on the day of your blood donation, you should wait until the effects wear off before going to your appointment. Avoid using cannabis immediately after you make your donation to avoid hypotension.


  1. Can You Donate Blood If You Use Cannabis? link.
  2. Role of cannabis in cardiovascular disorders link.
  3. An Outbreak of Synthetic Cannabinoid-Associated Coagulopathy in Illinois PubMed.
  4. Orthostatic hypotension after whole blood donation with various physiologic strategies to prevent fainting responses link.

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