The three main categories of research about aloe vera include anti-inflammatory, anti- bacterial, and anti-viral actions of Aloe vera. The juice is said to soothe digestive tract irritations such as colitis, ulcers and irritable bowel syndrome. Aloe's ability to encourage the release of pepsin (a gastric juice enzyme necessary for digestion) when the stomach is full is a possible reason for its ulcer-healing effects (Journal of the American Osteopathic Society, 1963, vol.62). In one study, oral use of Aloe for six months helped mitigate asthma symptoms in almost half of the participants. Eleven of twenty-seven patients studied who drank Aloe reported feeling better at the end of the study. Researchers think that results might be due to stimulation of the immune system, as well as naturally occurring anti-inflammatory agents in Aloe vera. Aloe vera is one of the only known natural vegetarian sources of Vitamin B12, and it contains many minerals vital to the growth process and healthy function of all the body's systems. Numerous studies worldwide indicate that aloe vera is a general tonic for the immune system, helping it to fight illness of all kinds. Various research studies are underway to explore the potential of aloe vera components to boost immunity and combat the HIV virus, and to treat certain types of cancer (particularly leukemia). It may even have a role to play in managing diabetes.