Short answer. It can, if the pressure amounted to undue influence. Article 1337 defines that as taking improper advantage of one's power over the will of another, depriving him of a reasonable freedom of choice, and it directs attention to family relations, mental weakness, ignorance and financial distress.

What the law says

There is undue influence when a person takes improper advantage of his power over the will of another, depriving the latter of a reasonable freedom of choice.

Civil Code, Article 1337 — Undue Influence. Read the full provision →

Pressure is not the test — freedom of choice is

Families argue, and a son who nagged his mother for months has not thereby undone the deed. What the article asks is whether the influence went so far as to deprive her of a reasonable freedom of choice, so that the signature records his will rather than hers. Two things therefore have to be shown together: that the relative held some power over her, and that he took improper advantage of it. Ordinary persuasion, even insistent and self-interested persuasion, is not enough on its own.

The article tells you what evidence to look for

It lists the circumstances to be considered: the confidential, family, spiritual and other relations between the parties, and whether the person alleged to have been unduly influenced was suffering from mental weakness, or was ignorant or in financial distress. That is close to a checklist. Who was living with her and controlling her medication, her money and her visitors. Whether she could read the deed. Who engaged the notary, who paid for it, who drove her there, and whether any of her other children knew. Her medical records around the date of signing are usually the centre of the case.

Consequence and deadline

Undue influence does not make the deed a nullity. Article 1330 makes a contract voidable where consent was given through mistake, violence, intimidation, undue influence or fraud, and Article 1390 confirms that such contracts bind until annulled in a proper action. The clock is the part people miss. Article 1391 gives four years, and in cases of undue influence the period begins from the time the defect of the consent ceases — commonly when the dominating relationship ends rather than when the family found out about the deed.

Neighbouring grounds worth checking

The same facts often support more than one ground. Article 1338 covers fraud, where insidious words or machinations induced the signing. Article 1332 shifts the burden in a common situation: where a party was unable to read, or the contract was in a language he did not understand, and mistake or fraud is alleged, the person enforcing the contract must show that the terms were fully explained. And under Article 1470 a price grossly below value is not itself a ground, but is evidence that may indicate a defect in the consent — which is exactly how these deeds tend to be priced.

Cases citing this provision

These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.

Related provisions

Note. Statute text quoted on this page is reproduced from the official enactment and is linked to the full provision. The explanation around it is general legal information from Vivas & Nobles Law Office, not legal advice. Whether it applies to your situation depends on facts only a lawyer reviewing them can assess.