I have suffered from indoor /outdoor allergies my whole life, with Itchy watery eyes congestion and massive sneezing attacks. I am allergic to tree pollen, grasses ,ragweed etc.. I am also allergic to indoor dust and mold. I have tried numerous allergy medications over the years. Benadryl made me too sleepy to function and do my daily activities. Claritin did not function well with all my allergies and seemed to not respond over time. Cetirizine is generic form of Zyrtec and works as well as the name brand. I take this product everyday all year long. If I forget a day ,I start to sneeze and feel all the effects of my allergies. I feel you need to take this product for at least a week to start to feel the full effects. I don't think it works as well for a one day problem like Benadryl. This is a great deal because it come in a 365 count package that last me the entire year. If you suffer form indoor/outdoor allergies I highly recommend this product .