Is "Dazzle White" safe to swallow?

I'm going to try out this Dazzle White brand teeth whitening gel tonight and on the label it says you shouldnt swallow any of it. But what if I use it and theres still some residue or something in my mouth after I rinse it out and I swallow the residue? Please help people tell me things like this have bleaches inside them that harm your body and I want to know if I should be careful or what should I do? ? ? ? ? :(