Before a romantic Caribbean weekend with her new boyfriend, Amanda Sanders decided she needed a little lift. So she called her doctor, Dr. Norman M. Rowe, to help out.

Dr. Rowe, a plastic surgeon in Manhattan, offers a quick fix — temporary breast enlargement. Instead of surgery, he injects a saline solution into the breasts, which briefly expands them.

The procedure began as as a way for women seeking breast enhancement to determine how they might look if they chose surgery. “We can take pictures and put them on computers, but those are sometimes unrealistic and can lead to false expectations,” Dr. Rowe said (giving new meaning, perhaps, to the term “falsies”). “So we said, if patients are unsure if they want implants, let’s put saline in the breast and let them live with it for 24 hours to see how they like it.”

It may not surprise that the injections were soon being requested as pick-me-ups for parties, weddings, bar mitzvahs, red-carpet events or, as with Ms. Sanders, a tropical vacation.