In response to political pressure, the National Cancer Institute did two studies involving Laetrile. The first was a retrospective analysis of patients treated with Laetrile. Letters were written to 385,000 physicians in the United States as well as 70,000 other health professionals requesting case reports of cancer patients who were thought to have benefited from using Laetrile. In addition, the various pro-Laetrile groups were asked to provide information concerning any such patients. Although it had been estimated that at least 70,000 Americans had used Laetrile—only 93 cases were submitted for evaluation. Wonder why?? The reviewers concluded that "the results allow no definite conclusions supporting the anti-cancer activity of Laetrile."
In July 1980, the NCI undertook clinical trials of 178 cancer patients who received Laetrile, vitamins and enzymes at the Mayo Clinic and three other prominent cancer centers. The results of the trial were clear-cut. Not one patient was cured or even stabilized. The median survival rate was 4.8 months from the start of therapy, and in those still alive after seven months, tumor size had increased. This was the expected result for patients receiving no treatment at all. In addition, several patients experienced symptoms of cyanide toxicity or had blood levels of cyanide approaching the lethal range.
So, the notion that B17 was banned because it helped people seems a little ridiculous and paranoid. Doesnt this seem more logical: it was banned because when held to scientific scrutiny it was proven to offer no benefit and in fact it potentially caused harm.