City conceded an early goal before being repeatedly caught out as Hereford winger Andrew Williams ran riot down the right flank.
The Bulls took the lead in only the second minute when the Lincoln defence failed to clear a corner and, when the ball came back into the box, Alan Connell slipped a low shot into the bottom corner.
Connell had another chance in the 14th minute when he rose above the Lincoln defence to meet a cross from Williams but headed wide.
Hereford keeper Wayne Brown saved his team in the 32nd minute when he came off his line well to block a shot from Spencer Weir-Daley.
But Williams tormented Paul Mayo and the defender was yellow-carded in the 34th minute for chopping down the winger on the edge of the box.
Two minutes later Williams again got the better of Mayo and his cross was fired in by Steve Guinan.
Lincoln took Mayo off at the break with Owain Warlow coming on. But, within a minute, the game was effectively over when Hereford scored their third goal.
A cross from Danny Thomas was weakly headed away by Jeff Hughes and Guinan took full advantage to score.
Guinan completed his hat-trick in the 55th minute after Lincoln keeper Alan Marriott could only parry a shot and the striker headed in. Referee Graham Salisbury initially ruled the effort out for offside but after a lengthy discussion with his assistant changed his mind and the goal stood.
Lincoln responded within 60 seconds. Scott Kerr fired over a free kick which was headed down by Nat Brown for Weir-Daley to score his third goal in two games.
But Hereford continued to create the better chances with Williams and Thomas both going close. Guinan could have scored his fourth goal in the 73rd minute when he was first to a cross from Thomas only to see Marriott save.
If Lincoln's problems were not bad enough they became worse in the 79th minute when youngster Leon Mettam was red-carded for a bad tackle on Dean Beckwith.
Lincoln never gave up and in stoppage time Hughes burst through before firing against a post. Then Paul Green had a header blocked on the line in a late flurry from the home team.