A regenerative agent for lead battery cells includes, for each liter of aqueous solution 40% of hydrogen peroxide, 1 ml to 70 ml of sulfuric acid with a density of 1 to 1.32 gcm.sup.-3, 0.1 g to 10 g of saccharides in solids and/or aldehydes or their derivatives, 0.1 g to 10 g of sodium and/or potassium bicarbonate and/or at least one hydroxide from the group of alkali metal hydroxides in solids and 0.1 g to 20 g, with an advantage 0.5 g to 2 g, of bisodium dinaphthylmethane disulfonic acid salt. The regenerative agent can also contain 0.1 g to 10 g of peroxoborate an/or tetraborate and/or sodium pyrophosphate in solids.