There were few chances in the opening 80 minutes of the game but Villa piled on the pressure in the closing stages and could have won it through Barry Bannan, Ciaran Clark or Ashley Young.
However, Bannan was denied by Ben Foster, Young the angle of post and crossbar and Clark his own bad finishing as Birmingham deservedly held on for a share of the spoils.
Alex McLeish's side had by far the better of the first half and will feel they should have had a penalty when Villa skipper Nigel Reo-Coker appeared to control the ball with his arm inside the box just before half-time.
They had the consolation of ending a run of six successive defeats against their local rivals, but this was a game lacking in quality and will not remain long in the memory.
Villa were the first to settle and a shortish back pass from Liam Ridgewell left Ben Foster having to react quickly to clear from Emile Heskey.
But the first half chance fell to Craig Gardner whose first time shot in the box was goal-bound but blocked by Villa defender James Collins.
A skidding pass into the box from Ashley Young only just eluded the run of Heskey as it ran through to Foster shortly after, before Gardner became the first player to be yellow carded by Howard Webb after 12 minutes for a lunge at Reo-Coker who reacted angrily.
Villa keeper Brad Friedel got his body behind a curling shot from Keith Fahey from the edge of the box, while Foster was relieved at the other end when his clearance was charged down by Reo-Coker and flew out of play for a goal-kick after another under-hit back pass from Ridgewell.
Birmingham then had strong appeals for a penalty rejected after 38 minutes when the ball appeared to hit the lower arm of Reo-Coker but Webb waved away their protests.
Zigic became the second City player to be yellow carded a minute later after he caught Collins when leading with his arm.
Friedel had to be alert to gather a low 25 yard drive from Gardner which gathered pace as it zipped off the surface but it was 56 minutes before Foster made his first meaningful save of the game when he parried away a low dipping attempt by Reo-Coker from outside the box.
Houllier made his first change two minutes after, with Steve Sidwell replaced by Barry Bannan.
Collins then made a superb block at full stretch to block a shot from Gardner, while Roger Johnson got in a crucial challenge on Heskey at the other end.
Blues defender Scott Dann and Reo-Coker both received bookings shortly after before Foster parried away a Bannan drive after good play by Heskey.
Clark headed just wide after substitute John Carew had turned the ball back across the box and he needed treatment after being caught by Foster.
Ashley Young clipped the angle of the crossbar and post with a rising drive as Villa searched in vain for a winner, but Zigic could even have won it for Blues when he headed wide from Larsson's free-kick.