Originally known as the Medal of the Immaculate Conception, but later became the Miraculous Medal due to the many miracles and graces granted through the intercession of Mary.
On July 18, 1830, St. Catherine Laboure was awaked by a child who asked her to come to the chapel. There she saw the Blessed Virgin Mary, who said,
“God wishes to charge you with a mission. You will be contradicted, but do not fear; you will have the grace to do what is necessary. Tell your spiritual director all that passes within you. Times are evil in France and in the world.”
Our Lady returned for a second apparition to St. Catherine on November 27, 1830. This time Mary was within an oval frame and standing on a globe (sorry flat earthers). Rays of light were coming out of gems from the many rings she was wearing. Mary said that these symbolized the graces that are shed upon those who ask for them. The oval frame had these words written around it: O Mary, conceived without sin pray for us who have recourse to thee.
The frame was rotating and on the other side appeared an M under a cross. At the bottom was the Sacred Heart of Jesus with a crown of thorns. Beside it was an Immaculate Heart of Mary with a sword through it. There were stars around the entire image. She noticed that some of these stars weren’t lit and asked Our Lady why. Mary said, “those are the graces which people forget to ask. And then requested that medals be made with these images and all who wear them will receive great graces.”
There have been many miracles documented with the Miraculous Medal. One of them was a 74 year old widow in 1834 who had a very difficult time walking after a cripping accident. She also needed assistance sitting and standing. After receiving the medal she went to Confession. Note: prayers are much more effective when in a state of grace. This was followed the next day by First Friday devotions and the start of a novena to the Sacred Heart of Jesus and Mary. She also venerated the medal she wore 20 times a day. On the 7th day of the novena, she was miraculous healed and was able to walk, climb stairs, and kneel without help.
You can find miraculous medals at any Catholic gift stores or online. Make sure the medal matches what Our Lady gave us. I’ve seen medals that are different designs or text. A prayer you can say with the medal is one from St. Maximilian Kolbe,
conceived without sin,
pray for us who have recourse to you,
and for all who do not have recourse to you,
especially the enemies of the Church
and those recommended to you.
You can also say other prayers like the Memorare, or any other devotion. A very simple prayer is the text on the medal,
conceived without sin,
pray for us who have recourse to thee.
Just put the medal on and brace yoursel for the graces and miracles that will come.