Both sides finished the game with 10 men as Hereford earned a point at struggling Plymouth.
Tom Barkhuizen gave the Bulls the lead when he latched on to Harry Pell's pass to slot in from close range.
But Nicky Featherstone's foul on Warren Feeney allowed Nick Chadwick to crash home from the penalty spot.
Hereford were then reduced to 10 when Michael Townsend received his second yellow before Argyle's Darren Purse saw red for a foul on Nathan Elder.
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Plymouth boss Carl Fletcher told BBC Radio Devon:
"At times the first half was OK. At times we weren't. It was up and down.
"After going a goal behind we came back well and poissibly could have won it.
"In terms of what we're looking at and what we want it wasn't fully there today."
Hereford boss Jamie Pitman told BBC Hereford & Worcester:
"We go into every game wanting to win it but obviously it was a big game given where both teams are in the league.
"Our last three performances previous to this one have not given us the rewards we have probably deserved.
"Today was another such case. To be fair to them they have had a few chances but I think we were good value for the win."