context: For thousands of years, people have used the gel from aloe vera leaves for healing and softening the skin. In fact, aloe has also long been a folk treatment for many maladies, including constipation and skin disorders. Modern-day research into aloe vera's benefits is mixed, with some evidence showing it can cause cancer in lab animals. There are no foods that contain aloe vera, so it must be taken in supplement or gel form. Some forms of aloe vera are safer to take than others, and chronic use is discouraged. Research backs up the ancient use of topical aloe vera as a skin treatment, at least for specific conditions. Studies have shown that aloe gel might be effective in treating psoriasis, seborrhea, dandruff, and minor burns and skin abrasions, as well as radiation-induced skin injuries. Aloe gel also seems helpful in treating the sores caused by genital herpes in men. There's also strong evidence that aloe juice, which contains latex, taken by mouth is a powerful laxative. In fact, aloe juice was once sold in over-the-counter constipation drugs. However, because aloe's safety was not well-established, the FDA ordered in 2002 that over-the-counter laxatives containing aloe vera either be reformulated or removed from store shelves. Aloe vera gel taken orally (by mouth) seems to help lower blood sugar levels in people with diabetes. It may also help to lower cholesterol. The results of aloe vera studies for other medical conditions have been less clear. Creams and gels with aloe vera vary in dosage. Some creams for minor burns have just 0.5% aloe vera. Others used for psoriasis may contain as much as 70% aloe vera. As an oral supplement, aloe has no set dose. For constipation, some use 100-200 milligrams of aloe juice -- or 50 milligrams of aloe extract -- daily as needed. For diabetes, 1 tablespoon of the gel has been used daily. High oral doses of aloe or aloe latex are dangerous. Ask your doctor for advice on how to use aloe. Researchers warn against the chronic use of aloe vera; however, if the aloe product is free of aloin -- an extract of the plant that has been found to cause colorectal cancer in rats -- it may be OK as a topical remedy for sunburn. Aloin is found between the outer leaf of the aloe plant and the gooey stuff inside. Side effects. Topical aloe vera might cause skin irritation. Oral aloe, which has a laxative effect, can cause cramping and diarrhea. This may cause electrolyte imbalances in the blood of people who ingest aloe for more than a few days. It can also stain the colon, thus making it difficult to visualize the colon during a colonoscopy. So avoid it for a month before having a colonoscopy. Aloe gel, for topical or oral use, should be free of aloin, which can be irritating to the gastrointestinal tract. Risks. Do not apply topical aloe vera to deep cuts or severe burns. People allergic to garlic, onions, and tulips are more likely to be allergic to aloe. High doses of oral aloe are dangerous. Don't take oral aloe if you have intestinal problems, heart disease, hemorrhoids, kidney problems, diabetes, or electrolyte imbalances. Interactions. If you take any drugs regularly, talk to your doctor before you start using aloe supplements. They could interact with medicines and supplements like diabetes drugs, heart drugs, laxatives, steroids, and licorice root. The oral use of aloe vera gel may also block the absorption of medicines taken at the same time. Given the lack of evidence about its safety, aloe vera supplements should not be used orally by children and women who are pregnant or breastfeeding.