At Dr. Larry Fanโ€™s plastic surgery practice in San Francisco, patients are clamoring to get their unwanted fat chilled away. Big drug and medical device companies have noticed.

Theyโ€™re known as non-invasive slimming procedures. In one, a device placed on fatty parts of the body cools the area to freezing temperatures — killing vulnerable fat cells. With no knives or anesthesia required, the procedures are โ€œwildly popularโ€ across all ages and with both men and women, said Fan, even at up to $4,000 for each treatment session.

The growing cosmetic trend is drawing corporate buyers. Two deals were struck within 24 hours this week: On Monday, drug giant Allergan Plc agreed to pay $2.48 billion for Zeltiq Inc., the manufacturer of CoolSculpting. On Tuesday Hologic Inc., a mammography machine maker, bought Cynosure Inc. for $1.65 billion on Tuesday for fat- and hair-removal devices and other aesthetic dermatology products.

โ€œBody contouring in our view is where facial injectables were 10 years ago,โ€ said Allergan Chief Commercial Officer Bill Meury, comparing CoolSculpting to Allerganโ€™s popular Botox injections. โ€œIt has excellent future growth prospects.โ€