Answer
Once perfected, a donation between living persons (inter vivos) is generally irrevocable. The donor may revoke it only on the grounds expressly allowed by the Civil Code: (i) the subsequent birth or existence of a child of the donor, the reappearance of a child believed already dead, or the donor's subsequent adoption of a minor child (Article 760); (ii) the donee's non-compliance with the conditions or charges imposed on the donation (Article 764); and (iii) acts of ingratitude by the donee as defined in Article 765 — such as committing an offense against the donor's person, honor, or property, or unduly refusing the donor support.
A donation is also limited by the legitime of compulsory heirs: a donation that impairs the legitime is inofficious and may be reduced upon the donor's death (Articles 752 and 771). The donor must always reserve, in full ownership or in usufruct, enough for his own support and that of his dependents.