Angel Raich suffers from nine different diseases, including an inoperable brain tumor.
The 38-year-old mother from Oakland, Calif., says marijuana is the only thing that helps relieve her chronic pain.
"If I didn't have cannabis in the morning, I couldn't move around," Raich said. "It's something that I have to have immediately. I have to have it every two hours."
Her home state of California allows the use of marijuana for medical purposes with a doctor's orders. But under federal law, you can be sent to prison for smoking pot.
In October 2002, Raich and Diane Monson, another California woman who uses medical marijuana, sued the federal government to prevent them from interfering with a patient's right to use medical marijuana.
"We've been labeled as criminals, and we're really not criminals," Raich said. "I'm a mom, I'm a good citizen. I'm just trying to stay alive, and I don't really think that's a crime."
The Supreme Court could issue a ruling in Raich v. Ashcroft as early as this Monday.
When the Supreme Court heard oral arguments in this case months ago, most of the justices seemed unreceptive to an exemption for medical use.
Citing federal law, Justice Antonin Scalia said it was "unlawful to possess it, period."
Ten other states permit the use of medical marijuana. But those laws could be in jeopardy if the high court finds that marijuana can not be used for any reason.
Angel Raich insists marijuana is the only drug that helps her and thousands of others.
"If they side against me, it means that they would be giving me a death sentence," Raich said.
Two other important Supreme Court cases may be decided on Monday. One involves the display of the Ten Commandments on public property. The other considers whether a city can confiscate your home to make way for private development projects like an office center or hotel.