The concept of excessive moisture causing damage to the skin is not a new one, and provides a rationale for many fundamental nursing interventions. Although traditionally thought of as a specific problem of continence care, it is a common problem encountered in many different patient groups. As a consequence the umbrella term moisture-associated skin damage (MASD) has been introduced to describe the spectrum of damage that occurs in response to the prolonged exposure of a patient's skin to perspiration, urine, faeces or wound exudate. It is generally accepted that MASD consists of four main separate conditions, each having slightly different aetiologies, all of which will be explored in this paper. Careful assessment can help distinguish between the four and enable appropriate prevention and treatment interventions to be implemented. Whatever causes the excessive moisture, effective interventions should consist of the adoption of a structured skin care regime to cleanseand protect, methods to keep the skin dry, controlling the source of the excessive moisture and treating any secondary infection.