How to read a medical cannabis label: THC, CBD and units

Legal cannabis labels contain a great deal of information in a small space. For someone using cannabis for medical purposes, several lines are especially important: the product category, THC and CBD amounts, the unit of measurement, the number of units and the intended use. Reading them together helps confirm that the product received matches the one discussed with the health care practitioner.

Start with the product and its intended use

First identify the category, such as dried cannabis, edible cannabis, an extract or a topical product. The label may also state an intended use, such as inhalation, ingestion or application to the skin. Two products showing similar numbers are therefore not necessarily interchangeable. Their format affects, among other things, how cannabinoids are absorbed and when effects may begin.

What do Total THC and Total CBD mean?

The front of the label must show the total amount or concentration of THC and CBD in the product. Health Canada explains that Total THC and Total CBD represent what the product could provide when used as intended. THC is the main cannabinoid responsible for intoxication and impairment. CBD is not intoxicating, but it can still have effects, and a product containing mostly CBD may also contain THC.

mg, mg/g and mg/ml: three different readings

The unit changes the meaning of the number. Milligrams (mg) express an amount. A value in mg/g is a concentration per gram, while mg/ml is a concentration per millilitre. To determine the amount in a particular volume or weight, both the concentration and the quantity used must be considered. Do not transfer a number directly from one format to another.

An example of concentration by weight

Health Canada gives the example of a 30 g package of dried cannabis labelled as 180 mg/g Total THC. The theoretical amount in the entire package is then 5,400 mg, or 180 multiplied by 30. This calculation describes the full package; it is not a recommended dose.

Total amount, per unit or per activation

Depending on the product format, a label may show a total amount for the package, an amount per unit or an amount per activation. A four-unit package listing 2.5 mg of Total THC per unit contains 10 mg in total. A spray listing 8 mg per activation dispenses 8 mg with each activation. Always check the number of units or the dispensing mechanism before comparing products.

Other useful information to check

• Ingredients and allergens: — extracts, topicals and edibles must display an ingredient list; allergen requirements vary by category.
• Weight, volume and units: — these put the concentration in context and show how many units are in the package.
• Storage: — follow the listed temperature, light or humidity conditions and keep the product in its original child-resistant packaging.
• Lot number: — keep it with the packaging date; this information is useful when reporting a quality concern or side effect.
• Packaging date: — this shows when the product was packaged. It is not automatically an expiry date, which the manufacturer may add voluntarily.
• Manufacturer contact details: — use them for a product quality question or complaint.

The label is not a dosing recommendation

Potency describes what the product contains; it does not by itself determine the amount that is appropriate for a person. Health Canada states that there is not enough scientific information to recommend a cannabis product for a specific health condition. Format, other medications, observed effects and the clinical situation also matter. Follow the plan established with your practitioner and request a reassessment before replacing a product or changing the amount used.

A simple check with every new delivery

• 1. Product: — confirm the category, format and intended use.
• 2. Cannabinoids: — compare Total THC and Total CBD with the expected product.
• 3. Unit: — identify whether the value is in mg, mg/g, mg/ml, per unit or per activation.
• 4. Safety: — check the ingredients, warnings and storage conditions.
• 5. Doubt or change: — contact the licensed seller with a product question and your health care practitioner with a clinical question.

How Coverleaf can support you

Coverleaf clinic practitioners can assess your situation and follow a medical cannabis plan when appropriate. No authorization or outcome can be guaranteed; every decision depends on the practitioner's assessment. The public callback form is only for your name, phone number, preferred contact time and general topic; do not enter sensitive medical information.

Official sources consulted

• Health Canada, How to read and understand a cannabis product label, updated May 13, 2026: — https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/personal-use/how-read-understand-cannabis-product-label.html
• Health Canada, Cannabis for medical purposes: Choosing a cannabis product, updated January 22, 2026: — https://www.canada.ca/en/health-canada/topics/accessing-cannabis-for-medical-purposes/cannabis-medical-purposes/choosing-cannabis-product.html
• Health Canada, Consumer information: Cannabis, published April 10, 2025: — https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/laws-regulations/regulations-support-cannabis-act/consumer-information.html