Many athletes at Rio are sporting red and purple marks on their body.
Those marks are not a hickey or bruise. A local acupuncturist says it is from an ancient Chinese therapy called cupping.
"We use these cups and we put fire in there and put the cup on the skin which creates a suction and brings the blood to the skin surface," said Nanie Carrillo, an acupuncturist at Acupuncture del Soul. "What that does is it creates a flow of blood, which creates a flow of energy."
This technique is used for soreness, muscle tension, asthma and inflammation.
Carrillo said that a cup can be left on for up to 10 minutes.
"Some people are afraid because we do use heat to create the suction so it can be a little scary at first, but after the first time people usually like it a lot," she said.
Instead of using fire on a glass cup, Carrillo explained that there is another method involving a plastic cup and pump.
One of her patients described the feeling of cupping as "comfortable and relaxing."
The red marks can last on the body anywhere from one day to a week.
Olympic champion Michael Phelps is just one of many who use this technique to relieve pain.