What are recurrent painful canker sores in the mouth commonly known as?

Recurrent painful canker sores in the mouth are commonly known as aphthous ulcers. These lesions are characterized by their painful nature and typically appear on the mucous membranes inside the mouth. They are usually round or oval with a gray or whitish base and a red halo. Unlike cold sores, which are caused by the herpes simplex virus and usually occur on the lips or around the mouth, aphthous ulcers are not caused by a viral infection. Additionally, terms like cantharides refer to a substance derived from blister beetles and have no relevance to canker sores. Herpes simplex refers specifically to a viral infection typically associated with cold sores and not the recurrent, non-viral lesions classified as aphthous ulcers. Thus, the term 'aphthous ulcers' accurately describes these recurrent and painful mouth sores.