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News Release

ISMP Warns that Medical Marijuana Product Labeling Problems Have Led to Errors

Horsham, Pa.—As state legalization of medical marijuana sales spreads, issues have arisen with confusing product labeling that has led to errors. Medical marijuana growers must confirm the contents of their products, so that information can be passed on to dispensaries and patients, but requirements vary by state. The Institute for Safe Medication Practices (ISMP) is warning that national regulation of medical marijuana labeling is necessary for states to be able to require that manufacturers follow safe labeling guidelines to protect consumers.

Medical marijuana comes in many different strains, each of which can contain chemicals such as tetrahydrocannabinol (THC) and cannabidiol (CBD) in varying amounts based on growing conditions. The amounts of THC and CBD are important to know in order to dose properly and manage a patient’s symptoms, but the way they are listed on product labels can be difficult to understand. The most recent issue of Safe Medicine™, ISMP’s newsletter for healthcare consumers, provides an overview of some of the medical marijuana labeling and packaging problems that exist and how they can lead to errors:

  • Inconsistent labeling—Amounts of THC and CBD in medical marijuana products can be listed as a ratio or a percent, and there is no requirement to consistently use one or the other, or the order in which they must appear. Patients may purchase a product labeled with a ratio only to see it expressed as a percent the next time they purchase.
  • Variable order of ratios—If the THC and CBD amounts are listed on the label as a ratio, which chemical is listed first can vary, leading to confusion.
  • No volume with percent—In place of ratios, some labels list the ingredients as a percent, but do not give the total volume in the container, making it hard to figure out exactly how much of each ingredient it contains.
  • Look-alike containers and labels—Similar looking packaging/labeling (especially from same grower) has led to confusion between products with different ratios of ingredients.
  • Unlabeled bottles and cartridges—For some liquid products and most vapor cartridges, only the outer box is labeled. If the box is discarded, the product could be confused with something else.
  • Missing information—Labels on some medical marijuana products may fail to list important ingredients.
  • Inaccurate labeling—There have been many reports of CBD-only products containing either no detectible CBD or significantly more CBD than is on the label. Studies have also found that some CBD only products contain detectable amounts of THC, which could cause a positive urine drug screening test.

Healthcare providers who recommend medical marijuana ideally should also recommend the best dose and frequency of use for each patient. Visiting a physician or pharmacist-run medical marijuana clinic or dispensary can ensure that a medical professional is available to help choose the right product and interpret label information to ensure correct dose is taken. Consumers should also ask for a demonstration of how to measure each dose of the product they select. Unfortunately, in some states, dispensers are not allowed to open the container and show the patient. Such regulations prohibit proper patient education and should be addressed.

Medical marijuana use errors can be reported to the ISMP National Medication Errors Reporting Program (ISMP MERP) at: All reports will automatically be forwarded to the US Food and Drug Administration, and submitters will not be identified without their express written permission. Please include product photographs as appropriate.

Efforts are currently underway to examine medical marijuana labeling issues and provide recommendations for improvement. ISMP is a member of an expert group convened by the Substance Use Disorders Institute of the University of the Sciences in Philadelphia to identify ways to improve medical marijuana labeling/packaging and prevent patient harm in the state of Pennsylvania. A report summarizing the group’s recommendations can be found at:

About the Institute for Safe Medication Practices
The Institute for Safe Medication Practices (ISMP) is the only 501c (3) nonprofit organization devoted entirely to preventing medication errors. ISMP is known and respected as the gold standard for medication safety information. For more than 25 years, it also has served as a vital force for progress. ISMP’s advocacy work alone has resulted in numerous necessary changes in clinical practice, public policy, and drug labeling and packaging. Among its many initiatives, ISMP runs the only national voluntary practitioner medication error reporting program, publishes newsletters with real-time error information read and trusted throughout the global healthcare community, and offers a wide range of unique educational programs, tools, and guidelines. In 2020, ISMP formally affiliated with ECRI Institute to create one of the largest healthcare quality and safety entities in the world. As an independent watchdog organization, ISMP receives no advertising revenue and depends entirely on charitable donations, educational grants, newsletter subscriptions, and volunteer efforts to pursue its life-saving work. Learn more at

For more information, contact:
Renee Brehio, Media Relations