Cosphagard® SA natural is 100% naturally sourced and COSMOS-approved salicylic acid made from natural wintergreen oil by mild fermentation and two-step purification. Salicylic acid has been sourced traditionally from willow trees. Willow bark extract has played a role in traditional herbal medicine in many cultures, and the extract of dried bark is still used as a drug in tea or natural medicine. Salicylic acid is a well-known active and listed Preservative that has been used for its antimicrobial, keratolytic and anti-inflammatory activity in products against acne and dandruff for many years.