Thomson was active in the 1540s and supplied medicines to
Regent Arran, his daughter
Barbara, Lady Gordon, and
Cardinal Beaton. He was the apothecary to Regent Arran, who paid him an annual fee. The Italian physician
Girolamo Cardano, who came to Scotland in 1552, described a pearl head dress worn by Thomson's daughter, comprising 73 Scottish pearls, "I saw on a girl's head, the daughter of Thomas Thomson in Edinburgh, about seventy three Scottish pearls, of equal and remarkable size". When
Patrick Ruthven, 3rd Lord Ruthven was unwell for three months in 1565 he was treated by the queen's French doctor, the physician David Preston, and Thomas Thomson. Thomas Thomson died in 1572. At his death the "drugs, unguents, plasters, spices, and other medicaments" in his shop and cellar were worth £300
Scots. Robert Henryson complained in 1575 that he was still owed money, and the price of a chest of gray sugar and a barrel of olive oil from Thomson's estate. ==Marriage and family==