I read on wikipedia that Aloe vera is "potentially carcinogenic" (List of herbs with known adverse effects). Hmm, that made me thinking. The reference is "Should we be concerned about herbal remedies" 2001 by Memory Elvin-Lewis. But in that paper she just quotes another paper titled "Anthranoid laxative abuse--a risk for colorectal cancer?" 1993 by Siegers et al, which conclues that "Anthranoid-containing laxatives--aloe, cascara, frangula, and rheum--may play a role in colorectal cancer" using a quite controversial analysis. A quick search finds another paper "Anthranoid laxative use is not a risk factor for colorectal neoplasia: results of a prospective case control study" 2000, G Nusko et al, that says "Neither anthranoid laxative use, even in the long term, nor macroscopic or marked microscopic melanosis coli were associated with any significant risk for the development of colorectal adenoma or carcinoma". I wonder, who might be interested in discrediting herbs and in particular Aloe?
Follow up 28 Nov 2011
A few other wikipedia articles cite a paper "Vitamins and minerals: not for cancer or cardiovascular prevention" published in 2010. I could not find the text of the paper, but from the journal content list this paper is only half a page long, and it does not have the author! I cannot believe how statements made positively and negatively polarized depending whether they are about chemical drugs or natural approaches.
Another citation from the wikipedia article "Cancer": "Some studies have found that consuming lots of fruits and vegetables has little if any effect on preventing cancer". The paper, it is being referred to, says "A very small inverse association between intake of total fruits and vegetables and cancer risk was observed in this study. Given the small magnitude of the observed associations, caution should be applied in their interpretation.". I just wonder who wants to write "Some studies have found that consuming lots of fruits and vegetables has little if any effect on preventing cancer" referring to a paper which does not make that statement. However there lots of studies which prove that vegetarian diet significantly reduces, for example, risk of colon cancer.
Someone wants to sell drugs badly and in large amounts.