SEATTLE - The state Health Department has set a final rule defining a 60-day supply of medical marijuana at 24 ounces and up to 15 plants.

The rule approved Thursday takes effect Nov. 1.

Previously, Washington's medical marijuana law allowed qualifying patients to have up to a 60-day supply, but didn't say how much that was. The result was a lot of confusion, with patients unsure how much they were allowed to have and police officers arresting people who they thought had too much.

State officials say the 24-ounce limit is the same as Oregon's, and more than allowed in some other states with medical marijuana laws, but less than allowed in several California counties.

Patient advocates argued for a higher limit.