One of the basic concepts of glandular therapy is that the oral ingestion of glandular material of a certain animal gland will strengthen the corresponding human gland. The result is a broad general effect indicative of improved glandular function. Thus, glandular therapy increases the tone, function, and/or activity of the corresponding gland. This principle is a mainstay of oriental therapy.
In case of infection of immune system deficiencies, thymus extracts and spleen extracts have been found to be quite useful. Glandular therapy is used extensively in the treatment of cancer, and AIDS.
Prior to the 1940s, glandular extracts were in wide use all over the world including the western world, and a considerable amount of research was in progress to support their use. With the development of antibiotics, and the advent of "modern" technological medicine, the research was concentrated on developing more and more antibiotics and other pharmaceutical drugs that was more profitable to the drug companies. The research in glandular therapy came to a halt as a result. Just because the glandular approach was not being pursued in clinical research does not invalidate the usefulness of the approach or diminish the validity of its therapeutic value. It is still one of the cornerstones to Traditional Chinese Medicine and India's Ayurvedic Medicine. Glandular therapy is also receiving renewed interest as a treatment for cancer.