HealthA2Z Allergy Relief Cetirizine HCL 10mg active ingredient is Cetirizine HCL,10 mg, an antihistamine for both indoor and outdoor allergy symptoms. These allergy pills help treat common allergy symptoms such as runny nose; sneezing; itchy, watery eyes. When used as directed, just one dose of HealthA2Z All Day Allergy works for a full 24 hours. Directions Adults and children 6 years and over one 10mg tablet once daily; do not take more than one 10mg tablet in 24 hours. A 5mg product may be appropriate for less severe symptoms