Ash Wednesday marks the beginning of the Lenten season and falls 40 days before Easter Sunday. During mass on Ash Wednesday, consecrated ash is applied on the forehead in the shape of a cross, by a priest, minister, or designated layperson. Fasting, abstinence, and repentance are practiced on this day. In 2010, the observation of Ash Wednesday falls on February 17.
In Biblical times, the imposition of ash on the foreheads of believers dates back to the 10th century where ash was a symbol of purification and penitence as described in Numbers 19:9, 17; Hebrews 9:13; Jonah 3:6; Matthew 11:21; and Luke 10:13.
"Remember, O man, that you are dust, and unto dust you shall return."
- (Latin: "Memento homo, quia pulvis es, et in pulverem reverteris.")
– Genesis 3:19
The ash applied to the forehead is not ordinary. Many churches follow the practice of burning the palms from the previous year's Palm Sunday. The ashes are then sprinkled with holy water and fumigated with incense.
A prayer is also uttered:
"God our Father, you create us from the dust of the earth. Grant that these ashes may be for us a sign of our penitence and a symbol of our mortality."
The ashes on one's forehead are meant to remind people that:
- they are human and mortal
- they must not revel in sins
- they must change for the better
- God created man by breathing life into dust, thus man is just dust and ashes without God 
Most people leave the mark on their forehead even after the mass, so as to “carry the sign of the cross into the world.” Some churches end services by washing off the ashes, symbolizing the cleansing of sins. 
Members of the Chinese Catholic community in Manila, Philippines were exempted from fasting for Ash Wednesday in 2008. The group asked Manila Archbishop Gaudencio Cardinal Rosales to grant them special dispensation from fasting and abstinence since Ash Wednesday fell on the eve of the Chinese New Year. The bishop issued the exemption but requested them to fast and abstain the day after their celebration. 
- ^ "Lent, the mark of ashes", bbc.co.uk (accessed 4 February 2010).
- ^ "Action on Smoking and Health", ASH Ireland (accessed on 4 February 2010).
- ^ "Chinese Catholics exempted from fasting on Ash Wednesday", GMANews.tv 5 February 2008 (accessed on 4 February 2010).