Medical Marijuana: Health Uses and Cannabis Laws

Author: Disabled World (DW)
Updated/Revised Date: 2 Nov 2026

Table of Contents:
Synopsis - Definition - About This Section - FAQs - Publications - Subtopics

Synopsis

An overview of medical marijuana and cannabis, covering cannabinoids such as THC and CBD, the conditions they may help treat, and how laws differ around the world.

At a Glance

• 1 - The cannabis plant has been used as medicine for thousands of years.
• 2 - Epidiolex, a purified form of CBD, is approved by the FDA for seizures in certain rare forms of epilepsy.
• 3 - Dronabinol and nabilone, synthetic cannabinoids, are FDA approved for nausea and vomiting caused by chemotherapy.
• 4 - As of June 2025, 41 U.S. states allowed medical cannabis and 24 allowed adult use, though it remains illegal under federal law.

Topic Definition

Medical Cannabis

Medical cannabis, also known as medical marijuana, refers to the use of the cannabis plant and its constituent cannabinoids - most notably tetrahydrocannabinol (THC) and cannabidiol (CBD) - as a therapy to treat disease or relieve symptoms. It is perhaps best known as an antiemetic, a treatment effective against nausea and vomiting, but it has been used across a wide range of conditions including chronic pain, muscle spasms, glaucoma, and appetite loss connected with illnesses such as cancer and AIDS. The plant has a long medicinal history stretching back thousands of years, and a synthetic form of THC is available as the prescription drug Marinol. Because cannabis affects the body in complex ways, its use in modern medicine remains debated, and its legal status for both medical and recreational purposes varies widely from one country and jurisdiction to another.

Overview

What is Medical Cannabis?

Medical cannabis, also known as medical marijuana, is the use of the cannabis plant and its chemical compounds, called cannabinoids, to treat disease or relieve symptoms. The best-known cannabinoids are tetrahydrocannabinol (THC), which causes the "high," and cannabidiol (CBD), which does not. The body also makes its own cannabinoid-like chemicals, such as anandamide, which act on the same receptors in the brain and body.

Several medicines made from cannabinoids are approved by the U.S. Food and Drug Administration (FDA). Dronabinol (Marinol and Syndros), a synthetic form of THC, and nabilone (Cesamet), a related synthetic cannabinoid, are approved to treat nausea and vomiting caused by cancer chemotherapy, and dronabinol was approved in 1992 to treat loss of appetite and weight loss in people with HIV/AIDS. Epidiolex, a purified form of CBD, is approved to treat seizures in certain rare forms of epilepsy, including Lennox-Gastaut syndrome and Dravet syndrome [National Center for Complementary and Integrative Health, 2019].

The cannabis plant has been used as medicine for thousands of years. Writings from ancient India show that its effects on the mind were known, and it was used for digestive problems, sleep problems, headaches, and pain. Its use in modern medicine remains controversial, and research into its benefits and risks continues.

List of Medical Marijuana and Cannabis Laws in Various Countries

What Does the Evidence Show?

According to the National Center for Complementary and Integrative Health (NCCIH):

• Chemotherapy nausea: Dronabinol and nabilone work better than a placebo for nausea and vomiting caused by chemotherapy, though they cause more side effects.
• Rare forms of epilepsy: Drugs containing cannabinoids may help treat certain rare forms of epilepsy.
• HIV/AIDS: Cannabinoid drugs may help with loss of appetite and weight loss.
• Chronic pain: Some evidence suggests a small benefit, which may be too small to matter to many patients.
• Multiple sclerosis: Cannabinoids may slightly improve muscle stiffness (spasticity) as reported by patients, but objective tests have not shown a significant improvement.
• Anxiety: A small amount of evidence suggests cannabis or cannabinoids might help reduce anxiety, but more research is needed.
• Glaucoma: Cannabis is not helpful for glaucoma. In early studies it lowered pressure in the eye less effectively than existing treatments.

Risks and Side Effects

Reported side effects of cannabis include dizziness, dry mouth, changes in appetite and mood, and short-term effects on memory and coordination, and they vary with the person and the dose. Cannabis can impair driving and can interact with other medicines, and some people who use it develop cannabis use disorder. Anyone thinking about medical cannabis should talk with a health care provider first, especially if they take other medicines.

Country Medical Marijuana and Cannabis Laws

The table below gives an overview of cannabis laws by country. Laws change often, so check current national and local rules before using or traveling with cannabis. The U.S. figures are from the National Conference of State Legislatures, as of June 26, 2025.

Frequently Asked Questions

What is the difference between THC and CBD?

THC is the main psychoactive compound in cannabis that produces a high, while CBD is non intoxicating and is often studied for potential effects on pain, anxiety, and seizures.

Do you need a prescription or card for medical marijuana?

Requirements vary by location, and many places that allow medical cannabis require a recommendation from a qualified provider or a registration card tied to a qualifying condition.

What conditions commonly qualify for medical cannabis?

Qualifying conditions differ by jurisdiction but often include chronic pain, nausea from chemotherapy, multiple sclerosis spasticity, epilepsy, and appetite loss related to serious illness.

Is medical marijuana legal everywhere?

No, legality varies widely between and within countries, so some places allow medical use, others allow only low THC products, and many still prohibit it entirely.

What are the possible side effects of medical marijuana?

Reported side effects can include dizziness, dry mouth, changes in appetite, altered mood, and short term effects on memory or coordination, which vary by person and dose.

How is medical cannabis taken?

It can be used in several forms including oils, capsules, sprays, edibles, and inhaled products, and the method chosen affects how quickly and how long the effects are felt.

Can medical marijuana interact with other medications?

Yes, cannabis can interact with certain medicines and affect how they work, so it is important to discuss all current medications with a healthcare professional before use.

Is there an FDA-approved medicine made from cannabis?

Yes, Epidiolex, a purified form of CBD, is approved by the FDA to treat seizures linked to Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. Other approved products, such as dronabinol, contain synthetic THC.

References

• National Center for Complementary and Integrative Health. (2019). Cannabis (marijuana) and cannabinoids: What you need to know.
• National Conference of State Legislatures. (2026). State medical cannabis laws.

Curated and edited by Ian C. Langtree, Founder and Editor-in-Chief, Disabled World. This section is maintained by the Disabled World editorial team. Last updated: 2 Nov 2026