The normal adult human body is composed of approximately 10^{^13} cells.

We also provide housing for a diverse flora of bacteria, viruses, fungi and parasites. A large proportion of our microbiome is non-cultivatable and can only be demonstrated by next generation DNA sequencing technologies.  It has been estimated that average human body has 100 trillion microbial cells in or on it,  outnumbering human cells by at least 10 to 1.

The diversity of skin microbiota according to location: