Cryotherapy (also called cryosurgery) is the application of extreme cold to destroy abnormal or diseased tissue. Cryotherapy is used to treat a number of diseases and disorders, especially skin conditions like warts, moles, skin tags and solar keratoses. Liquid nitrogen is usually used to freeze the tissues at the cellular level. The procedure is used often because of its efficacy and low rates of side effects.
The most common lesions treated with cryotherapy are:

• Solar keratoses
• Viral warts
• Seborrhoeic keratoses (senile warts)

Specialist dermatologists sometimes freeze small skin cancers such as superficial basal cell and in situ squamous cell carcinomas (Bowen's disease), but this is not always successful so careful follow-up is necessary.
Freezing may be the most suitable way of getting rid of many different kinds of surface skin lesion. It is relatively inexpensive, safe, and reliable. However, it is important that the skin lesion has been properly diagnosed. It should not be used to treat melanoma or any undiagnosed pigmented lesion that could be melanoma.