The odour of sanctity or odor of sanctity, according to the Catholic Church, is commonly understood to mean a specific scent (often compared to flowers) that emanates from the bodies of saint

Saint

A saint is a holy person. In various religions, saints are people who are believed to have exceptional holiness.In Christian usage, "saint" refers to any believer who is "in Christ", and in whom Christ dwells, whether in heaven or in earth...

s, especially from the wounds of stigmata

Stigmata

Stigmata are bodily marks, sores, or sensations of pain in locations corresponding to the crucifixion wounds of Jesus, such as the hands and feet...

.

Meanings

The odour of sanctity can be understood to mean two things:

1. An ontological state (a state of being), not usually related to an actual olfactory sensation, indicating that the individual possessing it is in a state of grace
   Grace (Christianity)
   In Christian theology, grace is God’s gift of God’s self to humankind. It is understood by Christians to be a spontaneous gift from God to man - "generous, free and totally unexpected and undeserved" - that takes the form of divine favour, love and clemency. It is an attribute of God that is most...
   
    (i.e., a state characterized by the absence of mortal sin
   Mortal sin
   Mortal sins are in the theology of some, but not all Christian denominations wrongful acts that condemn a person to Hell after death. These sins are considered "mortal" because they constitute a rupture in a person's link to God's saving grace: the person's soul becomes "dead", not merely weakened...
   
   ). Usually refers to the state of an individual's soul
   Soul
   A soul in certain spiritual, philosophical, and psychological traditions is the incorporeal essence of a person or living thing or object. Many philosophical and spiritual systems teach that humans have souls, and others teach that all living things and even inanimate objects have souls. The...
   
    at the time of death. Some canonized saints
   Canonization
   Canonization is the act by which a Christian church declares a deceased person to be a saint, upon which declaration the person is included in the canon, or list, of recognized saints. Originally, individuals were recognized as saints without any formal process...
   
    are said to have died in an odour of sanctity.
2. An actual odour (scent or aroma) present at the time of death and for some time thereafter.

Odour of sanctity and sainthood

The term "odour of sanctity" appears to have emerged in the Middle Ages

Middle Ages

The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

, at a time when many saints were raised to that status by acclamation

Acclamation

An acclamation, in its most common sense, is a form of election that does not use a ballot. "Acclamation" or "acclamatio" can also signify a kind of ritual greeting and expression of approval in certain social contexts in ancient Rome.-Voting:...

 of the faithful. In the absence of carefully written records, either by or about the individual, evidence of a saintly life was attested to only by personal recollections of those around him or her. It appears that the odour of sanctity occurring at the person’s death carried some weight in convincing the local ecclesiastical

Ecclesiology

Today, ecclesiology usually refers to the theological study of the Christian church. However when the word was coined in the late 1830s, it was defined as the science of the building and decoration of churches and it is still, though rarely, used in this sense.In its theological sense, ecclesiology...

 authority to "canonize

Canonization

Canonization is the act by which a Christian church declares a deceased person to be a saint, upon which declaration the person is included in the canon, or list, of recognized saints. Originally, individuals were recognized as saints without any formal process...

" the saint – to allow the faithful to venerate

Veneration

Veneration , or veneration of saints, is a special act of honoring a saint: an angel, or a dead person who has been identified by a church committee as singular in the traditions of the religion. It is practiced by the Eastern Orthodox Church, the Roman Catholic, and Eastern Catholic Churches...

 and pray to him or her.

Cause

There is a theory that the 'odor of sanctity' is merely a smell of acetone

Acetone

Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...

 and/or acetoacetic acid

Acetoacetic acid

Acetoacetic acid is the organic compound with the formula CH3CCH2CO2H. It is the simplest beta-keto acid group and like other members of this class is unstable.- Synthesis and properties :...

 caused by ketosis

Ketosis

Ketosis is a state of elevated levels of ketone bodies in the body. It is almost always generalized throughout the body, with hyperketonemia, that is, an elevated level of ketone bodies in the blood. Ketone bodies are formed by ketogenesis when the liver glycogen stores are depleted...

 caused by starvation

Starvation

Starvation is a severe deficiency in caloric energy, nutrient and vitamin intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death...

 caused by religious fasting

Fasting

Fasting is primarily the act of willingly abstaining from some or all food, drink, or both, for a period of time. An absolute fast is normally defined as abstinence from all food and liquid for a defined period, usually a single day , or several days. Other fasts may be only partially restrictive,...

.

Notable examples

Saint Teresa of Avila

Teresa of Ávila

Saint Teresa of Ávila, also called Saint Teresa of Jesus, baptized as Teresa Sánchez de Cepeda y Ahumada, was a prominent Spanish mystic, Roman Catholic saint, Carmelite nun, and writer of the Counter Reformation, and theologian of contemplative life through mental prayer...

 and Saint Maravillas of Jesus (a Spanish Discalced Carmelite

Discalced Carmelites

The Discalced Carmelites, or Barefoot Carmelites, is a Catholic mendicant order with roots in the eremitic tradition of the Desert Fathers and Mothers...

) were reported to have emitted heavenly scents immediately after they had died. Reputedly, Teresa of Avila's scent emanated throughout the whole monastery the moment she died. Saint Thérèse de Lisieux (known as "the Little Flower") was said to have produced a strong scent of rose

Rose

A rose is a woody perennial of the genus Rosa, within the family Rosaceae. There are over 100 species. They form a group of erect shrubs, and climbing or trailing plants, with stems that are often armed with sharp prickles. Flowers are large and showy, in colours ranging from white through yellows...

s at her death, which was detectable for days afterward. Likewise, the blood issuing from Padre Pio

Pio of Pietrelcina

Saint Pio of Pietrelcina was a Capuchin priest from Italy who is venerated as a saint in the Catholic Church. He was born Francesco Forgione, and given the name Pio when he joined the Capuchins; he was popularly known as Padre Pio after his ordination to the priesthood. He became famous for his ...

's stigmata allegedly emanated the smell of flowers.