At Dr. Larry Fan’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.

They’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 “wildly popular” 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.

“Body contouring in our view is where facial injectables were 10 years ago,” said Allergan Chief Commercial Officer Bill Meury, comparing CoolSculpting to Allergan’s popular Botox injections. “It has excellent future growth prospects.”