Originating in China, willow bark spread across the world as many began to see its medicinal properties, especially when combatting rheumatoid arthritis. Willow bark is known to relieve pain and possess anti-inflammatory properties. Even Hippocrates advised his patients to chew on the bark for relief from the pain and inflammation. Willow bark is effective because it contains the compound salicin, which is similar to aspirin.
A study was conducted to observe willow barks effect on back pain. Participants were given different dosages of willow bark. At the end of the study, they reported relief and some even became free of pain.