New data on the hydrogen behavior in barium cerate and strontium cerate and titanate have been obtained. The conclusions on the chemical state of hydrogen in cerates are drawn from the physico-chemical data on gas-solid exchange phenomena. The idea of different states of hydrogen in the same lattice is advanced. Both earlier and new data on the properties of alkaline hydroxides and hydrogenated Ba2YCu3O7 were used for a deeper understanding of the hydrogen behavior in the high-temperature proton conductors.