Chlorhexidine has been touted as the top antimicrobial agent in chewing gum to fight plaque. A study in the International Journal of Dental Hygiene compared CHX with other ingredients including zinc gluconate, eucalyptus and hydrogen peroxide. The report showed CHX was best at inhibiting plaque. CHX, magnolia and eucalyptus scored highest on preventing gingivitis. Urea and zinc gluconate were found to have no affect on plaque levels.