Actually, there are several states that allow medical marijuana, but Colorado and Washington have completely legalized it, like tobacco or liquor. No Dr.'s note needed...
Oh wow, really? Hmm...nope, I'm not a fan of smoking pot so I'll just stay here in Minnesota.
And it so happens Minnesota is a medical marijuana state. Kinda strict about it though, so unless your nausea is cause by the conditions described in the law, I'd say contact your local dealer, make sure you have some incense and self medicate in the privacy of your own home (as opposed to a bus stop or some such silliness)...
Minnesota
SF 2470 (200 KB) -- Signed into law by Gov. Mark Dayton on May 29, 2014
Approved: By Senate 46-16, by House 89-40
Effective: May 30, 2014
Approved Conditions: cancer (if the underlying condition or treatment produces severe or chronic pain, nausea or severe vomiting, or cachexia or severe wasting), glaucoma, HIV/AIDS, Tourette's syndorme, ALS, seizures/epilepsy, severe and persistent muscle spasms/MS, Crohn's disease, terminal illness with a life expectancy of under one year.
The commissioner will consider adding intractable pain and other conditions, and must report findings no later than July 1, 2016.
Possession/Cultivation: The Commissioner of Health will register two in-state manufacturers for the production of all medical cannabis within the state. Manufacturers are required to ensure that the medical cannabis distributed contains a maximum of a 30-day supply of the dosage determined for that patient.
"Medical cannabis" is defined as any species of the genus cannabis plant delivered in the form of (1) liquid, including, but not limited to, oil; (2) pill; (3) vaporized delivery method that does not require the use of dried leaves or plant form. Smoking is not a method approved by the bill.