Party members suspected of corruption, bad management or breaking with the party line are liable to be hauled before discipline inspection commissions, set up to deal with internal party discipline and to monitor abuses.
As economic reforms have gathered pace, corruption has become probably the single most damaging issue for the party's standing.
As a result, there have been consistent campaigns to root out corrupt officials and give maximum media coverage to a few, high-profile punishments.
For example, Shanghai party chief Chen Liangyu, who was also a member of the Politburo, was arrested in 2006 accused of mis-using the city's pension fund.
More often, powerful party members are usually able to protect themselves, their families and proteges from any enquiries or public criticism.
And because it is the party which investigates the party - it is not prepared to tolerate outsiders monitoring its members' behaviour - the commissions are always prone to interference from higher up.
On the occasions that the party has acted against senior members, its motives have been questioned.
For example, experts say the fall of Mr Chen is as much about Chinese President Hu Jintao's attempts to consolidate his power as it is about corruption.
Nevertheless, the discipline inspection commissions do have privileged access to information about people. Their control over networks of informers and personal files makes them particularly feared.