The doctrine of death-sickness (marḍ al-maut) is concerned with the legal effect of transactions entered into by persons in their death-sickness, persons who are termed in Arabic marīḍ and who may be alternatively called here, for the sake of convenience, “dying persons”.

As the second major branch of the ultra vires doctrine, the law of death-sickness basically extends the limitations imposed upon bequests to cover gifts made by a dying person. But here the law is also concerned with those other acts and transactions of a dying person which may affect the substance and the devolution of his estate, such as sales, acknowledgments of debt, marriage and divorce. Because these are acts of immediate effect which are not, like bequests, postponed until death and which therefore may affect the gross, as opposed to the net, estate, the doctrine of death-sickness has the broader purpose of protecting the interests of the dying person's creditors just as much as those of his legal heirs.

Rationale of the doctrine

Although a dying person may, in terms of sanity and prudent judgment, be perfectly competent to engage in transactions, he is placed under interdiction in order to protect the interests of his creditors and his heirs, to the extent, basically, that any transaction which offends their interests will be effective only if they ratify it. The law aims only to protect mature interests, that is to say, in the case of an heir, when his right to succeed to part of the estate has crystallised, and in the case of a creditor, when his right has become attached to the estate.