Seventeen people have been arrested in a number of early morning drugs raids across Oxfordshire and Buckinghamshire.
Officers executed 22 warrants at properties across the two counties, including two homes in Oxford and addresses in Bicester and Worminghall.
Twelve men and five women were held on suspicion of various offences, including supplying drugs.
Police said they had recovered quantities of cocaine and cannabis as well as money and a CS gas canister.
Det Supt David Poole said: "Today's arrests are the culmination of an extensive investigation by Thames Valley Police.
"We will take any action necessary to stop the supply of illegal and dangerous drugs, which cause so much harm to our communities."
The arrested men, aged between 23 and 62, and the women, aged between 28 and 51, are being held in custody.