Some people with MS wonder if cannabis could help relieve their symptoms. More than half of those with the disease say they'd consider trying it if it was legal and there was more scientific data available.

Studies on the use of cannabis and multiple sclerosis (MS) symptoms tell us this:

• Cannabis extract taken in a capsule form can help relieve muscle stiffness (spasticity) and spasms.
• The extract may reduce pain.
• A mouth spray form possibly reduces spasticity, pain and bladder urgency.

But the use of cannabis to treat MS symptoms is complicated.

All cannabis-based medicines have side effects. Some can be serious, such as:

• Difficulty with attention or concentration
• Dizziness or faintness
• Dry mouth
• Hallucinations
• Loss of balance and falls
• Depression or psychosis

Cannabis is a federally controlled substance in the United States. Medical marijuana and cannabis programs are legal in more than half of the country.

To date, the Food and Drug Administration has approved two synthetic forms of marijuana for medical use: dronabinol (Marinol) and nabilone (Cesamet). They are capsules that you take by mouth.

Both drugs are approved for treating chemotherapy-related nausea and vomiting that does not get better with standard treatment. Dronabinol is also approved for people with AIDS who have loss of appetite with weight loss. At this time, the drugs are not approved for other uses.

A cannabis extract mouth spray, nabiximols (Sativex), is not currently available in the U.S. Also, smoked marijuana has not been adequately studied for safety and benefit.

The role of cannabis for MS symptoms isn�t fully clear. Future research will help determine more about cannabis' benefits and risks, and compare its effects to other therapies used to treat spasticity, pain and other MS symptoms.