1,3-Benzodioxol derivatives, the new compounds, represented by the formula: ##STR1## AND THE PHARMACOLOGICALLY ACCEPTABLE ACID-ADDITION SALTS THEREOF ARE PROVIDED, WHEREIN R.sub.1 and R.sub.2 are lower alkyls or the both together may form a divalent alkylene, R.sub.3 is a lower alkyl, phenyl, halogen-substituted phenyl or benzhydryl group, n is an integer of 2 or 3, and X stands for carbonyl (CO) or methylene (CH.sub.2) bridge. The compounds in which X stands for the methylene exhibit durable anti-histamic activity with low toxicity, and are useful for therapeutic purposes, while the compounds in which X stands for the carbonyl bridge are easily convertible by reduction into the former compounds.