Your knee hurts, and every little movement is sheer torture for your aching back too. If medication or other therapy fails to help, acupuncture can bring relief.

Inserting fine needles into the skin and underlying tissues can also combat allergies, menstrual pain and even moderately severe depression.

"Acupuncture helps primarily in cases of chronic and acute pain such as migraines and arthrosis, but also stress and asthma," said Helmut Ruedinger, vice chairman of the Hamburg-based German Medical Association for Acupuncture (DAEGFA).

Timo, a 30-year-old from Berlin, suffered from severe, stabbing headaches during his studies, particularly when he was at the computer writing his final paper.

"First they prescribed physiotherapy, then massages," he recalled. "Only acupuncture helped." After just eight acupuncture sessions, Timo was completely pain-free - and still is.

Critics continue to question the technique's effectiveness, though.

In 2006 in the German city of Siegburg, the Federal Joint Committee (G-BA), a body made up of doctors and public health insurance company officials that helps regulate Germany's medical services, included acupuncture in the list of treatments covered by public insurance - but only for chronic knee and back pain.

The G-BA said it was unclear whether other ailments could be successfully treated with acupuncture. In those cases the patient has to pay out of their own pocket.

An extensive series of tests found no differences between acupuncture and medication in treating headaches and migraines. Experts who conducted the tests said that improvement in the patients' condition may have been merely subjective, with psychological factors playing a role.

Acupuncture is a mainstay of traditional Chinese medicine. It seeks to influence the flow of what is believed to be the body's vital life force by inserting needles at certain points. There are more than 360 acupuncture points, which are arranged along meridians or pathways.

The meridians are the same on both sides of the body, and the points are associated with particular locations in the body.

Western acupuncturists surmise that the effects of acupuncture have a physiological basis. "When a needle is inserted into the body, it strikes small nerves that send impulses to the spinal cord and brain," Ruedinger said.

The brain then gives the signal for the release of endorphins, which cause patients to feel happy and relaxed.

"Acupuncture affects different people differently," Ruedinger warned. The needles eliminate some people's symptoms entirely, while they do nothing for other people. "One reason for this could be fields of interference in the body such as scars or infections, which hamper the effect," Ruedinger said.

The procedure has few side effects. Sometimes no bruising occurs.

Patients often wonder how to find the right acupuncturist. "The most important thing is how much experience the therapist has," Ruedinger said. If a physician has the additional title of acupuncturist, it means that he or she has had at least 200 hours of recognised training.