Active Ingredients: Aluminum Chloride 12% Inactive Ingredients: Sodium Bicarbonate; Water Uses: Treats excessive perspiration. Reduces underarm wetness. Doctor recommended. Prescription strength. Certain Dri contains Aluminum Chloride the ingredient prescribed by doctors to patients with excessive perspiration or Hyperhidrosis. Laboratory studies prove that Aluminum Chloride is more effective and longer lasting than other ingredients found in anti-perspirants yet safe when used as directed. Even after 72 hours in an independent test Certain Dri Prescription Strength Anti-Perspirant proved more effective and longer lasting (June 2005).