Aphthous stomatitis stomatitis may show herpes virus within the epithelium of the mucosa, but without any productive infection. In some persons, attacks of ulceration occur at the same time as asymptomatic viral shedding and elevated viral titres. In some instances, recurrent mouth ulcers may be a manifestation of an allergic reaction. Possible allergens include certain foods ("e.g.", chocolate, coffee, strawberries, eggs, nuts, tomatoes, cheese, citrus fruits, benzoates, cinnamaldehyde, and highly acidic foods), toothpastes, and mouthwashes. Where dietary allergens are responsible, mouth ulcers usually develop within about 12–24 hours of exposure. Sodium lauryl sulphate (SLS), a detergent present in some brands of toothpaste
The Canon of Medicine anatomy, and physiology. The book explains the causes of health and disease. Avicenna believed that the human body cannot be restored to health unless the causes of both health and disease are determined. He defined medicine ("tibb") as follows: Avicenna begins part one by dividing theoretical medicine and medical practice. He describes what he says are the "four causes" of illness, based on Aristotelian philosophy: The material cause, the efficient cause, the formal cause, and the final cause: Avicenna's thesis on the elements of the cosmos is described by Gruner as "the foundation of the whole "Canon"". Avicenna insists here