The Family Code of the Philippines, embodied in Executive Order No. 209, series of 1987, as amended, governs the institution of marriage and the grounds for its dissolution or nullification. Annulment of marriage is a judicial remedy that applies exclusively to voidable marriages—those that are valid and legally binding from the moment of celebration until a competent court declares them annulled. Unlike a declaration of nullity of marriage under Articles 35, 36, 37, 38, and 41 (void marriages that are inexistent from the beginning and produce no legal effects), annulment treats the marriage as existing until the decree is issued. The grounds for annulment are exhaustively enumerated in Article 45 of the Family Code and must have existed at the time the marriage was solemnized. These grounds are exclusive; no other cause, however compelling, may serve as basis for annulment.

Once annulled, the marriage is deemed never to have taken legal effect for purposes of future relations between the parties, although children conceived or born before the decree are considered legitimate (Article 54). The decree also requires the liquidation of the absolute community of property or conjugal partnership, provision for support, and custody and support of common children.

The Six Grounds under Article 45

Article 45 provides six specific causes, each with its own requisites and, in most cases, a possibility of ratification through free cohabitation.

1. Lack of Parental Consent (Article 45(1))
A party who was eighteen years of age or over but below twenty-one at the time of marriage, and whose marriage was solemnized without the written consent of the parents, guardian, or person having legal charge over him or her, may seek annulment.
The Family Code (Article 14) still requires such consent even though the age of majority is eighteen. The absence of consent renders the marriage voidable. However, the marriage is ratified and can no longer be annulled if, after reaching twenty-one, the party freely cohabited with the other as husband and wife. Only the aggrieved party (the one whose consent was lacking) may file the petition.

2. Unsound Mind (Article 45(2))
Either party must have been of unsound mind at the time of the marriage. The incapacity must exist at the moment of celebration; subsequent insanity is irrelevant.
The marriage may be annulled unless the insane party, after regaining sanity, freely cohabited with the other as husband and wife. The sane spouse, the guardian, or the person having legal charge of the insane party may file the petition at any time before the death of either spouse. The insane party himself may file within five years after regaining sanity.

3. Consent Obtained by Fraud (Article 45(3))
The consent of either party must have been obtained by fraud. Article 46 expressly limits the meaning of “fraud” to only one circumstance: concealment by the wife of the fact that, at the time of the marriage, she was pregnant by a man other than her husband.
Any other misrepresentation—such as concealment of wealth, social status, criminal record, or even a sexually transmissible disease (already covered by another ground)—does not constitute fraud under Article 46. The marriage may be annulled unless the injured party, with full knowledge of the fraud, freely cohabited with the other thereafter. Only the injured party may file the petition within five years after discovery of the fraud.

4. Consent Obtained by Force, Intimidation, or Undue Influence (Article 45(4))
The consent of either party must have been vitiated by force, intimidation, or undue influence. The violence or threat must be serious and must have caused the party to have no real choice. Mere persuasion or ordinary influence is insufficient.
The marriage is ratified and cannot be annulled if, after the force, intimidation, or undue influence disappeared or ceased, the injured party freely cohabited with the other as husband and wife. Only the injured party may file within five years from the time the force, intimidation, or undue influence ceased.

5. Physical Incapacity to Consummate the Marriage (Article 45(5))
Either party must have been physically incapable of consummating the marriage with the other at the time of the celebration, and such incapacity must continue and appear to be incurable.
This ground refers to physical impotence (impotentia copulandi), not psychological incapacity (which is a ground for declaration of nullity under Article 36). Sterility is not impotence. The incapacity must be permanent and incurable at the time of marriage. There is no ratification clause for this ground; the injured party may file the petition within five years after the marriage.

6. Affliction with a Serious and Incurable Sexually Transmissible Disease (Article 45(6))
Either party must have been afflicted with a sexually transmissible disease that is serious and appears to be incurable at the time of the marriage.
The disease must be grave enough to endanger the health of the other spouse or the offspring and must appear incurable. Mere infection with a treatable STD does not suffice. Like impotence, there is no ratification clause. The injured party may file within five years after the marriage.

Who May File and Prescriptive Periods (Article 47)

The right to file an annulment petition is not available to just anyone and is subject to strict prescription periods to prevent stale claims:

For lack of parental consent: the aggrieved minor party within five years after attaining twenty-one.
For unsound mind: the sane spouse or legal representative at any time before the death of either party; or the insane party within five years after regaining sanity.
For fraud: the injured party within five years after discovery of the fraud.
For force, intimidation, or undue influence: the injured party within five years from the time the vice disappeared or ceased.
For physical incapacity and STD: the injured party within five years after the marriage.

After the prescriptive period lapses, the marriage is deemed ratified and can no longer be annulled on that ground.

Procedure for Annulment

The petition must be filed in the Regional Trial Court of the province or city where the petitioner or respondent has resided for at least six months before the filing (Rule 4, Rules of Court, in relation to Article 49). The action is in rem; the respondent must be personally served with summons, or, if unknown, publication may be allowed. A public prosecutor must investigate and certify that no collusion exists between the parties (Article 48). The court may appoint a guardian ad litem for minor children.

Evidence must clearly and convincingly prove the ground. Mere allegations are insufficient. Psychological evaluations, medical certificates, or eyewitness testimony are commonly required depending on the ground.

Effects of the Decree of Annulment (Articles 50–54)

A final decree of annulment produces the following effects:

The marriage is dissolved as to the future; the parties are restored to the status of single persons and may remarry.
The absolute community or conjugal partnership is liquidated in accordance with the rules on separation of property.
Legitimate children conceived or born before the decree remain legitimate and are entitled to support and custody arrangements based on their best interest.
The innocent spouse may be awarded moral damages and attorney’s fees if the ground is attributable to the fault of the other spouse.
The decree must be recorded in the local civil registry and in the registries where the marriage was registered.

The Family Code deliberately makes annulment difficult to obtain precisely to uphold the constitutional policy of protecting marriage as an inviolable social institution. Only the six grounds listed in Article 45, proven within the strict prescriptive periods and without ratification by cohabitation, will suffice. Psychological incapacity, irreconcilable differences, or simple incompatibility are not grounds for annulment; they fall under declaration of nullity or, in appropriate cases, legal separation under Article 55.

This exhaustive statutory framework ensures that annulment remains an extraordinary remedy reserved for marriages that were defective from the outset in the specific manners enumerated by law.