Medical leeches are making a comeback. That might sound gross, but don’t worry — bloodletting is not on the rise. Rather, a better understanding of what leeches can do for human blood flow and inflammation has defined a clear and useful role for the slimy suckers.

Today, in the United Kingdom, leeches are often used after reconstructive surgery to help prevent veins from clogging up when fingers or ears are reattached. While plastic surgeons often are able to reconnect arteries, the veins initially prove more difficult. Leech bites create a temporary path for the blood flow until capillaries forge new bonds and the veins regain their proper role.

In a 2002 survey, 80 percent of plastic surgery centers in the United Kingdom and Republic of Ireland said they used leeches. Only four reported that any patients had refused the treatment. The pain-relieving qualities of leeches also make them useful in the treatment of osteoarthritis.

A recent German study found patients with osteoarthritis of the knee had less pain and more functionality after just one treatment with eight leeches. The researchers say their results are similar to the relief offered by nonsteroidal anti-inflammatory medicines often prescribed for arthritis. But the leeches present fewer — and less severe — side effects. The primary one is short-term itching at the site of the bites.

Modern medicine theorizes that leeches help because their saliva contains a substance that stops inflammation and blood clotting.

In 2004, the Food and Drug Administration granted a French firm permission to market leeches in the United States as medical devices. So if you can overcome the heebie-jeebies, leeches might help you get by with less ibuprofen.