Brewer's: Drat 'em!
A variant of Od rotem! The first word is a minced form of the word God, as in “Od's blood!” “Od zounds!”=God's wounds, “Od's bodikins,” etc. See Odd's. A correspondent in Notes and Queries suggests “[May] God out-root them!” but we have the words drattle and throttle (to choke) which would better account for the a and the o, and which are also imprecations.