Police sniffer dogs have been brought on to a university campus, in a "zero-tolerance" approach to drugs.
The University of Buckingham has also given local police passes to access the university at any time, as a deterrent to any drug use.
Sir Anthony Seldon, the university's vice-chancellor, says illegal drugs are a "key factor" in mental health problems among young people.
He has warned against universities "turning a blind eye" to drug use.
The search by sniffer dogs did not find anything illegal, but the university says that it wants to send a message that it is tightening checks and that it will not offer any tacit acceptance of student drug use.
There will be regular police patrols on campus, says the university.
The move is part of the university's project to improve students' well-being.
Sir Anthony has been a high-profile campaigner for universities to take more responsibility for the pastoral care of students.
He has argued that too many universities have neglected the well-being of young people who are leaving home for the first time.
As part of this, he argues that universities need to address drug use among students, which can contribute to mental health problems.
Buckingham has a project to become a "positive health university" and to challenge what Sir Anthony calls a "crisis of mental health in our universities".
He wants university staff to take a more active in role in supporting students and to intervene at an early stage if there are emotional problems.
The well-being project wants to promote a healthier campus culture and to cultivate "mental health literacy" and "emotional resilience".
"The culture of heavy drinking, a "blind eye" to drug-taking, and tacit endorsement of a "laddish culture" will be tackled head on," says Sir Anthony.