Two people have been arrested as part of an investigation into spikings in Nottingham.
A man has also been arrested in Lincoln as part of an inquiry into similar allegations there.
In both cases, the police say the suspects have not been linked to incidents which involve chemicals being administered via a needle.
Women describe 'spiked needle attacks'
Sky News reported how women were feeling ill and blacking out after allegedly being attacked with needles in cities such as Nottingham, Liverpool, Cardiff, Manchester, Leeds and Newcastle.
The two men in Nottingham - aged 18 and 19 - were detained on Friday morning on suspicion of conspiracy to administer poison with intent to injure, annoy or aggrieve.
It came following "a number of enquiries, including reviewing CCTV footage and also working really closely with our venues and staff in the city", according to a police statement.
Superintendent Kathryn Craner, of Nottinghamshire Police, said: "I would like to reiterate that these arrests have not been made in connection with a specific case or incident reported to us over the last few weeks of both drink spiking and spiking by a needle."
The man in Lincoln, aged 35, was arrested in the early hours of Friday morning on suspicion of possession of drugs with intent to administer them.
Police said the suspected offence "doesn't involve a needle".
The Lincolnshire constabulary added: "The issue of spiking has seen an increase as we have come out of lockdown. We also may be getting more reports following our highlighting of the issue along with the media coverage.
"We welcome increased reporting and we want anyone who suspects they may have been a victim to come forward."
Speaking on the arrests in her jurisdiction, Superintendent Craner said: "These two arrests come after a plea from myself and the force for people to come forward and report any incidents to us."
She added: "We are continuing to thoroughly investigate any reports made to us and these two arrests show that we are working extremely hard and working positively with our licensed premises to investigate any reports made to the force.
"We will act positively on any information that the public provide to us, as can be seen today and this is why I would like people to continue to come forwards.
"I would like to personally say a huge thank you to those who have continued to make reports throughout last night.
"I would like to reassure people that as a force we are placing a lot of resources into these enquires.
"If you believe you have been spiked, feel you have been spiked, suspect anyone else has been spiked or see any suspicious activity our message remains the same and we want to encourage everyone to come forward immediately."
Crimes can be reported by calling 101 or online, but police advise to always call 999 in an emergency. Information can be passed anonymously to Crimestoppers on 0800 555111
