A biopsy instrument comprises a cutting head having first and second co-operable jaws movable with respect to a support between open and closed states, and a jaw drive for moving one or both of the jaws into the closed state to take a biopsy sample in response to an actuating input from a user. The jaw drive is user-adjustable between first and second cutting modes differentiated by the response of the jaws to the actuating input. In the first cutting mode, both jaws may move equi-angularly with respect to the support between the open and closed states； in the second cutting mode, one jaw may remain stationary with respect to the support such that only the other jaw moves between the open and closed states.
