Sen. Elizabeth Warren has drawn attention to what many call an epidemic: the deaths of thousands of people each year from opioid painkillers and heroin.

Two-thousand fourteen was the worst year and saw more than 47,000 Americans die due to opioid painkillers, according to a Centers for Disease Control and Prevention report.

Warren has a solution. She wants the CDC to study "the use, uptake, and effectiveness of medical marijuana as an alternative to opioids for pain treatment in states where it is legal," reports Vox.com.

"Our country is faced with an opioid epidemic that only continues to grow at an alarming pace.  Opioid abuse is a national concern and warrants swift an immediate action," Warren wrote in a letter to CDC head Thomas Frieden, reports the New York Daily News.

Medical marijuana remains illegal under federal law. This is in contrast to 23 states, including Massachusetts, plus Washington, D.C., allowing the plant to be allowed for some medical purposes. Meanwhile, marijuana can be legally used recreationally in Colorado, Washington state, Oregon and Alaska.

Warren in her letter asked the CDC to investigate "the impact of the legalization of medical and recreational marijuana on opioid overdose deaths," reports The Guardian.

A study published in the Journal of American Medical Association found "moderate-quality evidence" for medical marijuana treating chronic pain and muscle stiffness among multiple sclerosis patients and "low-quality evidence" for the plant improving nausea and vomiting due to chemotherapy, weight gain in HIV infection, sleep disorders and Tourette's syndrome.