Q. I would like you to know about medical marijuana for cancer. In her late 30s, my wife was diagnosed with pancreatic cancer, stage 4a. It was a 6 centimeter tumor that had grown around the hepatic artery and portal vein.

At first I thought marijuana was just for nausea caused by her chemo, but then I found a study in the journal Cancer Research (July 1, 2006). It showed that cannabinoids specifically fight pancreatic tumor cells.

I changed her diet and started her on a regimen, and she is now cancer-free. The regimen is being studied at the University of Wisconsin. I hope others can benefit from medical marijuana.

A. For years, marijuana research was suspected of being a way to rationalize people getting high. But as a recent article in Science News points out, scientists are now starting to take it seriously (June 19, 2010). The article you cite demonstrates that compounds from marijuana make pancreatic tumor cells commit suicide.

Other cancer researchers have followed up with studies on its effectiveness against a range of tumors in test tubes, including breast, colon, glioblastoma brain tumors and lymphoma, a blood cancer. None is yet in a clinical trial, but this will be an interesting field to watch. We are delighted your wife had such a good response to such a difficult-to-treat cancer.

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Q. I tried the soap-under-the-sheet remedy for leg cramps. It was successful, but it didn’t last. Then my doctor prescribed Qualaquin 325mgcapsules, and they work like a charm.

This medication has quinine and is usually used for the treatment of malaria. Now I take one every other night, with excellent results.

A. The Food and Drug Administration has only approved Qualaquin (quinine) for the treatment of malaria. Any other use is considered “off label” and inappropriate. On July 8, 2010, the FDA issued the following warning: “Qualaquin should not be used for night time leg cramps.”

The agency has received reports of serious blood reactions and kidney damage. In some cases, people have died from quinine toxicity.

Some readers have suggested that replacing the soap after several weeks might improve its effectiveness.

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Q. What is the story about the toxic effects of zinc in denture creams?

A. Too much zinc, whether from dental adhesives or taken as a supplement, can lead to a copper deficiency. The possible consequences are anemia and neurological problems.

Lisa Sanders, M. D., described a case in The New York Times Magazine (Sept. 6, 2009) in which a 64- year-old woman overused denture cream. Her balance was affected, along with the strength in her legs. She was almost unable to walk.

Her doctors were puzzled, but when they discovered that she had superhigh levels of zinc and almost no copper in her bloodstream, they tracked the problem to the adhesive she used to keep her ill-fitting dentures in place.

GSK, maker of Super PoliGrip, has reformulated its denture adhesive cream. The company urges consumers to look for the zinc-free product. The FDA is working with other manufacturers to reduce the risk that consumers might be exposed to excessive levels of zinc in their denture creams.