I once heard a preacher stating that there are instructions in the Old Testament which prohibit the faithful from getting their body tattooed. I wish to know whether there are any teachings from the side of Catholic Church explicitly warning its members against tattooes .
There is no official Catholic condemnation against getting tattoos. I know some priests who have tattoos! The whole idea of getting tattoos is to say the least very discouraged by the Church.
First of all, the Church has not made any kind of formal decision on the matter of tattoos. There is some Biblical evidence on this, for example, a passage in Leviticus that says:
"You shall not make any cuttings in your flesh on account of the dead or tattoo any marks upon you: I am the Lord" (Lev. 19:28).
Yet, it seems that this prohibition was present so as to avoid the people of Israel from following the pagan mourning practices of the Canannites. Moreover, these Old Testament ritualistic laws are not binding on Christians.
The Church does say that we should avoid practices that mutilate or damage our body, as you can see in no. 2296 of the Catechism.
The question of tattoos was on the mind of at least one pope. Pope Hadrian I forbade the usage of tattoos on one's body in 787 AD.
In 787 AD, Pope Hadrian banned tattooing. It still thrived in Britain until the Norman Invasion of 1066. The Normans disdained tattooing. It disappeared from Western culture from the 12th to the 16th centuries. - A Brief History of Tattoos
Nevertheless there were a few exception from this ban of tattoos by Pope Hadrian I.
Christian tattooing rarely enters the written record but when it does, it does so in interesting ways. Pope Hadrian I, in 787 AD, banned tattooing (since it was associated with heathen practices) but there was an exemption for religious tattoos since they would “bring spiritual rewards.”
In the Medieval period, mentions of tattoos become more numerous including clerics (such as Dominican priest and German mystic Heinrich Suso (1295-1366) who tattooed the name of Jesus over his heart). - Christian Tattooing
Why did British sailors get the Crucifixion scene tattoo on their backs.
European sailors were known to tattoo the crucifixion on their backs to prevent flogging (since it was a crime to deface an image of Christ). - A Brief History of Tattoos
Here is a sample of a genuinely Catholic tattoo from Seven Types of Christian Tattoos.