Harry Crawford came on for the injured Johnny Herd and put Blues ahead in the 36th minute when Joe Heath's attempted clearance fell to the striker, who looped the ball over Bulls' goalkeeper Adam Bartlett from six yards.
Forward Barry Corr doubled the advantage in the 65th minute when he side-footed home after Bartlett parried Lee Sawyer's shot from inside the box and into the Irishman's path.
Corr was on hand again to make it 3-0 two minutes later when he headed Sean Clohessy's right-wing free-kick into the goal from close range at the back post.
Crawford wrapped up the scoring from the penalty spot in stoppage time after Joe Colbeck's professional foul on Sean Clohessy saw the midfielder sent off and referee Karl Evans award the spot-kick, which Crawford tucked into the bottom right corner under a diving Bartlett.
Hereford had looked shaky early on but recovered to see Stuart Fleetwood and former Shrimpers loanee Waide Fairhurst forced saves out of Southend goalkeeper Glenn Morris.
And the Southend goalkeeper did well to deal with a point-blank header from Bulls skipper Michael Townsend.
Southend 4-0 Hereford: Match Report - view commentary, squad, and statictics of the game as it happened.
Source: DSG
