By Michelle Roberts
BBC News Online health staff
Gwyneth Paltrow caused a stir at a New York film premiere this week in a low cut top revealing a back covered in large circular bruises.
Her low-cut top revealed the cupping bruises
At first glance they looked like large love bites, but in fact they were caused by a form of alternative therapy.
Gwyneth had cupping, a kind of acupuncture.
It involves placing heated cups over the skin to encourage blood flow and ease stress, aches and pains.
What is cupping?
Cupping has been practised for thousands of years for the treatment of disease and pain.
It is a form of acupuncture that focuses on the movement of blood, energy - called qi - and body fluids, such as lymph - which circulates around the body's tissues.
Oriental medicine states pain is due to stagnation of these systems. This stagnation can be a result of injury or stress.
Cupping is believed to stimulate flow of blood, lymph and Qi to the affected area. Its uses include relieving pain in the muscles, especially back pain from stiffness or injury, and clearing congestion in the chest, which can occur with colds and flu.
How it's done
The therapist takes a number of glass cups, which look like small fish bowls. Each cup is heated with a naked flame. The cup is then quickly applied to the skin. This creates a vacuum.
The suction anchors the cup to the body and the area of skin covered is drawn up a few millimetres into the cup.
The cups are then left on the body whilst the area beneath is treated and the energy, or qi, is moved.
Cupping is usually used on its own, but can be combined with other therapies.
Tim Handley had conventional acupuncture and cupping therapy for a painful shoulder.
He told BBC News Online: "I had four treatments and it really knocked it on the head. It was brilliant. After the first time I had it I felt absolutely fantastic. The difference was so tangible. It was wonderful.
"It felt quite strange because the suction was enormous. It was intense but not painful. You could feel the blood being drawn into the muscle."
Like Gwyneth, he was bruised afterwards, but the marks vanished quickly.
"It looked hilarious. They were deep purple, amazing bruises. But it's not damage as such. They are 'healthy bruises' and they disappeared very quickly - within a week. I would have it done again."
Mike O'Farrell, CEO of the British Acupuncture Council said: "Although cupping does leave noticeable marks that can look alarming, it is not painful during or after treatment.
"This is a successful method as seen by the thousands of patients who use it. However, as with all medical treatments it is important to seek out a registered practitioner."
But Professor Edzard Ernst from the department of complementary medicine at the University of Exeter said, while cupping was relatively safe, it could cause burns.
He added: "There is no evidence for its efficacy. It has not been submitted to clinical trials, but there have certainly been satisfied customers for 3,000 years."