This one's bound to make some pretty big waves: Yet another new study backs marijuana for medicinal purposes in a big way.

This time, researchers have found that pot can not only help beat pain -- as people who already take it for that purpose, legally and illegally, have been saying all along -- but it may even help steer patients away from dangerous and addictive painkillers.

And that includes the meds responsible for some of society's biggest drug problems: opioid painkillers.

Twenty-one chronic pain patients who were already taking either long-acting morphine or long-acting oxycodone were given marijuana vaporizers to use for five days -- in a hospital, where they could be carefully monitored in case any complications arose.

Researchers were especially worried that the pot might boost levels of opioids in the blood to dangerous levels. In reality, it led to no changes at all -- while delivering 33 percent more pain relief to the morphine patients and 20 percent more pain relief to the oxycodone patients.

The patients didn't experience any major side effects, beyond feeling "high" after getting their marijuana dose.

No one in the study actually took fewer meds -- but since the patients were already growing more resistant to their opioid painkillers and got extra relief from marijuana, the indication is that eventually they could cut back on the meds if they were allowed to stick with the pot.

Of course, the study does have its problems: It didn't have a placebo, for one. And it was small -- but size is almost always a problem when it comes to studies on medical marijuana.

Researchers simply can't get the funding they need for bigger studies since marijuana isn't exactly popular with the folks who control the purse strings.

But the studies we do have are pretty clear: Medical marijuana comes with some very real benefits... and minimal risk.

Despite what you've heard, it's not even addictive in most cases. Sure, people can overdo it -- but that's a risk we already take each day with every drug already on the market (especially opioid painkillers).

This isn't a popular opinion, but it's a scientific one -- not to mention a humane one: For some conditions, especially chronic pain, marijuana is safe and effective -- and that means it should also be legal.