I'm about to order some myself. It does need watering down with de Ionized Water ! It's whether it's worth getting the 35% version or buying it at a more straight usable strength of 7/8%.
I intend using it to increase the speed of destroying organisms in my stomach which have set up home and don't want to be ejected. Iodine and hydrogen peroxide and hydrochloric acid are what I intend using. HCL gets a bit expensive so that's why I want the other two items.