Gyro bought biochemical and marketing communications specialists Cicero in March, and Swedish biotechnology and brand communications specialists Dowell Stubbs in July.
In this latest deal, Gyro has acquired a UK company that specialises in advertising and marketing consultancy for the healthcare sector.
London-based Woolley Pau has a turnover of £3m and a staff of 25 working on advertising and marketing for brands, including over-the-counter and prescription medicines.
Louise Pau, joint founder and managing director of Woolley Pau, said: "This move makes perfect sense for us. We have a fantastic reputation for creativity but until now have lacked the global stature and group resources to compete consistently with the healthcare networks."
Gyro International provides integrated communications to clients including Sony, Virgin Atlantic, American Express, Adobe and HP.
The Woolley Pau office has become part of the international Gyro network, which has offices in London, Manchester, Stockholm, Geneva, San Francisco, Amsterdam, Dublin, Hamburg and Paris.
Richard Glasson, chief operating officer at Gyro International, said: ''Strategically, Woolley Pau is a significant acquisition for Gyro. We have identified healthcare as a key market for growth and we are extremely close to being able to offer our clients a total healthcare offering. This will be completed shortly with a further acquisition planned in this sector before Christmas.''