**Corynebacteriaceae** is a family of bacteria that includes gram-positive bacteria. Some species are normal components of the normal microflora of humans and animals, others are found in association with sick people. Within this group, the genera Corynebacterium, Nocardiopsis and Nocardia are distinguished. Previously they belonged to the genus Micrococcus. The names were changed due to problems in determining their taxonomy, up to the identification of the family, which was considered to be the family of organisms closest to Actinomyces. Up to 3 species have been identified as Corynebacterium sp. intermedium and Cor. minutissimum. The boundaries between species are often very blurred, partly due to their similar appearance and the similarity of some of their properties even despite the difference in DNA. The term "Tenue" is Latin for weak or subtle. More accurately, we can say that this is a fine-mixed bacillus.