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Dr. Sanjay Gupta reacts to the Justice Department's announcement that it won't block laws that have legalized marijuana in states like Washington and Colorado.
Dr. Sanjay Gupta explains why mixing drugs can be fatal, and why it is so difficult to recover from heroin addiction.
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Dr. David King had finished running the Boston Marathon when the bombs went off, and he rushed to the hospital to help.
CNN's Dr. Sanjay Gupta talks to Wolf Blitzer about pictures of Albert Einstein's brain that were just released.
Dr. Sanjay Gupta goes to Massachusetts to get answers from the facility that made the contaminated injections.