Detectives are investigating reports that two women were spiked by injection while on a night out in Brighton.
The incidents are reported to have taken place in the evening on Tuesday (October 19) and in the early hours of Wednesday morning (October 20).
Chief Superintendent Justin Burtenshaw, Divisional Commander for Brighton, said: "We are talking with two victims who felt unwell after a night out in the city and suspect they had been injected. They are being supported by officers.
"We are still at a very early stage in our investigation and a number of enquiries are being made.
"We take all reports incredibly seriously and ask anyone who believes they have been a victim or witness to spiking to contact us. We also encourage people to report any suspicious behaviour to us - either online or via 101, or by calling 999 in an emergency."
Officers say they are increasing patrols and will continue to work closely with licensed premises on initiatives to help keep patrons safe.
Ch Supt Burtenshaw added: "We are aware of the national media and the worry and anxiety this may cause those wanting to enjoy the night-time economy.
"Everyone should be able to enjoy themselves safely and to support this there are officers who will be on patrol across the city over the weekend.
"Our Licensing Teams are working hard with venues to raise awareness about spiking and ensuring that appropriate measures are in place to prevent this from happening."