Guy's and St Thomas' Charity awards grants to facilitate improvements to health services in the London boroughs of Lambeth and Southwark. Grants fund a wide range of projects: from small schemes which improve the patients' environment, to major initiatives which involve the purchase of cutting-edge equipment to diagnose or treat illness.

Grants to improve healthcare are awarded to Guy's and St Thomas' NHS Foundation Trust, South London and Maudsley NHS Foundation Trust, and to Lambeth and Southwark Primary Care Trusts. Grants for research which benefit these NHS Trusts are also awarded, principally to King's College London.