A motion to dismiss is the legal equivalent of a general demurrer. Citizens for Parental Rights v. San Mateo County Bd. of Educ. (1975) 51 Cal.App.3d 1, 34.

A demurrer (or motion to dismiss) is limited to matters appearing on the face of the challenged pleading or matters which must or may be judicially noticed. Blank v. Kirwan (1985) 39 Cal.3d 311, 318.

The sole question on a motion to dismiss is whether or not a cause of action has been stated. Citizens at 7, fn. 4.

The Code of Civil Procedure, section 581 provides that:

1. An action may be dismissed in any of the following instances:
   1. With or without prejudice, upon written request of the plaintiff to the clerk, filed with papers in the case, or by oral or written request to the court at any time before the actual commencement of trial, upon payment of the costs, if any.
   2. With or without prejudice, by any party upon the written consent of all other parties.
   3. By the court, without prejudice, when no party appears for trial following 30 days’ notice of time and place of trial.
   4. By the court, without prejudice, when dismissal is made pursuant to the applicable provisions of Chapter 1.5 (commencing with Section 583.110).
   5. By the court, without prejudice, when either party fails to appear on the trial and the other party appears and asks for dismissal.
2. A plaintiff may dismiss his or her complaint, or any cause of action asserted in it, in its entirety, or as to any defendant or defendants, with or without prejudice prior to the actual commencement of trial.
3. Except as otherwise provided in subdivision (e), the court shall dismiss the complaint, or any cause of action asserted in it, in its entirety or as to any defendant, with prejudice, when upon the trial and before the final submission of the case, the plaintiff abandons it.
4. After the actual commencement of trial, the court shall dismiss the complaint, or any causes of action asserted in it, in its entirety or as to any defendants, with prejudice, if the plaintiff requests a dismissal, unless all affected parties to the trial consent to dismissal without prejudice or by order of the court dismissing the same without prejudice on a showing of good cause.
5. The court may dismiss the complaint as to that defendant when:
   1. Except where Section 597 applies, after a demurrer to the complaint is sustained without leave to amend and either party moves for dismissal.commencement of trial, upon payment of the costs, if any.
   2. Except where Section 597 applies, after a demurrer to the complaint is sustained with leave to amend, the plaintiff fails to amend it within the time allowed by the court and either party moves for dismissal.
   3. After a motion to strike the whole of a complaint is granted without leave to amend and either party moves for dismissal.
   4. After a motion to strike the whole of a complaint or portion thereof is granted with leave to amend the plaintiff fails to amend it within the time allowed by the court and either party moves for dismissal.
6. The court may dismiss without prejudice the complaint in whole, or as to that defendant, when dismissal is made under the applicable provisions of Chapter 1.5 (commencing with Section 583.110).

(More provisions can be found in CCP § 581.)

A court may dismiss an action, with or without prejudice, upon plaintiff’s written request to the clerk at any time before commencement of trial. CCP § 581(b)(1). Generally, the plaintiff has an absolute right to dismiss a lawsuit, neither the clerk nor the trial court has any discretion in the matter, and voluntary dismissal terminates the trial court's jurisdiction over the matter. O'Dell v. Freightliner Corp., 10 Cal.App.4th 645, 659 (1992). Dismissal is effective upon tender of the request and all subsequent proceedings are void. Aetna Cas. & Sur. Co. v. Humboldt Loaders, Inc., 202 Cal.App.3d 921, 931 (1988).

The court has discretion to dismiss an action for failure to prosecute. Code of Civil Procedure Section 583.410, subdivision (a), provides:

The court may in its discretion dismiss an action for delay in prosecution pursuant to this article on its own motion or on motion of the defendant if to do so appears to the court appropriate under the circumstances of the case.

The California Rules of Court list the factors to be considered in determining whether to dismiss an action that has not been brought to trial within two years after the action was commenced. They include the extent to which the parties engaged in any settlement negotiations or discussions, the diligence of the parties in pursuing discovery, the nature and complexity of the case, the law applicable to the case, the nature of any extensions of time or other delay attributable to either party, the condition of the court’s calendar and the availability of an earlier trial date, and whether the interests of justice are best served by a dismissal of the case. Cal. Rules of Court, Rule 3.1342, subd. (e). “[W]hen there is an entire absence of any showing of good cause for delay,” an action may properly be dismissed. City of Los Angeles v. Gleneagle Development Company (1976) 62 Cal.App.3d 543, 561.

The Code of Civil Procedure, 583.420(a) sets out the other grounds of court removal:

1. Service is not made within two years after the action is commenced against the defendant.
2. The action is not brought to trial within the following times:
   1. Three years after the action is commenced against the defendant unless otherwise prescribed by rule under subparagraph (B).
   2. Two years after the action is commenced against the defendant if the Judicial Council by rule adopted pursuant to Section 583.410 so prescribes for the court because of the condition of the court calendar or for other reasons affecting the conduct of litigation or the administration of justice.
3. A new trial is granted and the action is not again brought to trial within the following times:
   1. If a trial is commenced but no judgment is entered because of a mistrial or because a jury is unable to reach a decision, within two years after the order of the court declaring the mistrial or the disagreement of the jury is entered.
   2. If after judgment a new trial is granted and no appeal is taken, within two years after the order granting the new trial is entered.
   3. If on appeal an order granting a new trial is affirmed or a judgment is reversed and the action remanded for a new trial, within two years after the remittitur is filed by the clerk of the trial court.
2. The times provided in subdivision (a) shall be computed in the manner provided for computation of the comparable times under Articles 2 (commencing with Section 583.210) and 3 (commencing with Section 583.310).

The court also has inherent authority to dismiss an action (recognized in the Code of Civil Procedure § 583.150). Exercise of this power has generally been confined to “sham” actions, or cases involving prejudicial delay in prosecution for less than the statutory periods. Two significant factors in exercising this discretionary power are: (a) whether the plaintiff's conduct was “severe and deliberate”; and (b) whether alternatives less severe than dismissal are available to remedy the situation. “[S]ound exercise of discretion requires the judge to consider and use lesser sanctions unless the court's authority cannot possibly be otherwise vindicated.” Lyons v. Wickhorst, (1986) 42 Cal.3d 911, 917.